The Effectiveness of Symptom Checkers for Self-Diagnosis ... · Confidential: For Review Only 1 The Effectiveness of Symptom Checkers for Self-Diagnosis and Triage: Beyond “Googling”

Confidential: For Review O

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The Effectiveness of Symptom Checkers for Self-Diagnosis

and Triage: Beyond “Googling” Symptoms

Journal: BMJ

Manuscript ID: BMJ.2015.025489

Article Type: Research

BMJ Journal: BMJ

Date Submitted by the Author: 17-Feb-2015

Complete List of Authors: Semigran, Hannah; Harvard Medical School, Health Care Policy Linder, Jeffrey; Brigham and Women's Hospital, Medicine; Harvard Medical School, Gidengil, Courtney; RAND Corporation, ; Boston Children's Hospital, Infectious Diseases

Mehrotra, Ateev; Harvard Medical School, Health Care Policy; Beth Israel Deaconess Medical Center, General Internal Medicine and Primary Care

Keywords: Symptom checkers, Internet, Antibiotic prescribing, mHealth

https://mc.manuscriptcentral.com/bmj

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The Effectiveness of Symptom Checkers for Self-Diagnosis and Triage:

Beyond “Googling” Symptoms

Hannah Semigran,1

Jeffrey A. Linder,1,2

Courtney Gidengil,1,3,4

Ateev Mehrotra,1,5

1 Harvard Medical School, Boston, MA

2 Division of General Medicine and Primary Care, Brigham and Women’s Hospital, Boston, MA

3 RAND Corporation, Boston, MA

4 Division of Infectious Diseases, Boston Children’s Hospital, Boston, MA

5 Division of General Internal Medicine and Primary Care, Beth Israel Deaconess Medical Center,

Boston, MA

Corresponding Author:

Ateev Mehrotra, MD, MPH

Harvard Medical School

180 Longwood Avenue

Boston, MA 02115

617-432-3905

[email protected]

This study was funded by the United States’ National Institute of Health, (National Institute of Allergy

and Infectious Disease - Grant # R21 AI097759-01).

Conflict of Interest: All authors are affiliated with Harvard Medical School. Harvard Medical School’s

Family Health Guide is used as the basis for three symptom checkers evaluated. None of the authors

have been or plan to be involved in the development, evaluation, promotion or any other facet of

Harvard Medical School-related symptom checkers.

Word Count: 3,130

Tables: 5

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SUMMARY:

Objective: Use of the internet for self-diagnosis is common. Symptom checkers are online tools which

use computer algorithms to help patients with self-diagnosis and/or self-triage. Despite the growth in

use of such tools, performance of symptom checkers has not been assessed. Our objective was to

determine the accuracy of online symptom checkers’ diagnostic and triage advice.

Design: Audit study of all available symptom checkers using 45 standardized patient (SP) vignettes

divided equally into three categories based on problem urgency: emergent care required (e.g.,

pulmonary embolism), non-emergent care reasonable (e.g., otitis media), and self-care reasonable (e.g.,

viral upper respiratory illness).

Main outcome measures: For symptom checkers that provided a diagnosis, our main outcomes were

whether the symptom checker listed the correct diagnosis first or at all in the list of potential diagnoses

(n = 650 SP evaluations). For symptom checkers that provided a triage recommendation, our main

outcomes were whether the symptom checker appropriately recommended emergent care, non-

emergent care, or self-care (n = 516 SP evaluations).

Results: The 20 symptom checkers identified provided the correct diagnosis first in 33% (95% confidence

interval [CI], 30-37) of SP evaluations, listed the correct diagnosis at all in 60% (95% CI 56-63) of SP

evaluations, and provided the appropriate triage advice in 56% (95% CI 51-61) of SP evaluations. Triage

performance varied by condition urgency, with appropriate triage advice provided in 80% (95% CI 74-86)

of emergent cases, 55% (95% CI 47-62) of non-emergent cases, and 34% (95% CI 27-41) of self-care

cases (p<0.001). Performance across individual symptom checkers on appropriate triage advice ranged

from 33% (95% CI 19-48) to 78% (95% CI 64-91) of SP evaluations.

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Conclusions: Symptom checkers had deficits in both diagnosis and triage. Triage advice was generally

risk-averse; symptom checkers encouraged users to seek care for conditions where self-care was

reasonable.

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Introduction

The public is increasingly using the internet to research their health concerns. More than a third of

adults in the United States regularly use the internet to self-diagnose what ails them,1 and the United

Kingdom’s online patient portal for national health information, NHS Choices, reports over 15 million

visits per month.2 While there is a wealth of online resources to learn about specific conditions, self-

diagnosis for acute conditions is often limited to simply typing a list of symptoms into an internet search

engine.3 Three quarters of online health searchers begin with search engines like Google, Bing, or

Yahoo.1 Between 2008 and 2014 health-related searches using Google UK increased 13.5%.

3 Internet

search engines can lead users to confusing and sometimes unsubstantiated information.4-6

Recently,

there has been a proliferation of more sophisticated programs called symptom checkers that attempt to

more effectively diagnose patients and direct them to the appropriate care setting.

Using computerized algorithms, symptom checkers ask users a series of questions about their symptoms

or require users to input their symptoms themselves. The algorithms vary and may use branching logic,

Bayesian inference, or other methods. Private companies and other organizations, including the NHS,

the American Academy of Pediatrics, and the Mayo Clinic, have launched their own symptom checkers.

One symptom checker, iTriage, reports 50 million uses per year.7 Typically symptom checkers are

accessed via websites, but some are also available as apps for smart phones or tablets.

Symptom checkers serve two main functions: facilitating self-diagnosis and assisting with triage. The

self-diagnosis function provides a list of diagnoses usually rank ordered by likelihood. The diagnosis

function is typically framed as helping educate patients on the range of diagnoses that might fit their

symptoms. The triage function informs patients whether they should seek care at all and, if so, where

(i.e. accident & emergency department, general provider’s (GP) clinic) and with what urgency (i.e.

emergent or within a few days). Symptom checkers may supplement or replace telephone triage lines,

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which are common in primary care.8-10

To ensure the safety of medical mobile apps, the United States

Congress is considering regulation of apps that “provide a list of possible medical conditions and advice

on when to consult a health care provider.”11 12

Symptom checkers have several potential benefits. They can encourage patients with a life-threatening

problem to seek emergent care.13

For patients with a non-emergent problem that does not require a

medical visit, these programs can reassure patients by recommending that they stay home. Simple acute

conditions such as viral upper respiratory illness are common and for approximately a quarter of acute

respiratory illness visits, patients do not receive any intervention beyond over-the-counter therapy,14

and over half of patients receive unnecessary antibiotics.15-18

Decreasing unnecessary visits saves

patients’ time and money, deters overprescribing of antibiotics, and may increase general practitioners’

(GP) capacity to manage more patients – a critical issue given GP workload in the United Kingdom

increased by 62% from 1995 to 2008.10

However, there are several key concerns. If patients with a life-threatening problem are misdiagnosed

and told to not seek care, their health could worsen, increasing morbidity and mortality. Alternatively, if

patients with minor illnesses are told to seek care, in particular in an accident & emergency department,

such programs could increase unnecessary visits and therefore result in increased time and costs for

patients and society.

To our knowledge, no previous study has systematically evaluated the diagnostic and triage

performance of symptom checkers. To evaluate the ability of symptom checkers to provide an accurate

diagnosis and appropriate triage advice, we audited all available symptom checkers using 45

standardized patient (SP) vignettes.

Methods

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Identifying symptom checkers

We identified all available symptom checkers, which we defined as online internet resources for

personalized self-diagnosis and self-triage, through internet searches, literature review, and

consultation with experts in the field. We identified 28 symptom checkers that were in English, free, and

publicly-available. We excluded symptom checkers that used the same underlying logic or algorithm as

other symptom checkers. Australia’s Health Direct Symptom Checker shares a license and similar triage

output with England’s NHS Symptom Checker. The American Academy of Pediatrics’ Healthy Children

Symptom Checker and the Swedish Kids Symptom Checker both utilize an electronic version of a

common nurse triage protocol.19

Everyday Health uses the same algorithm as FreeMD; MedicineNet and

RxList use the same as WebMD, the AARP uses the same as Healthline; Kaiser Permanente is powered

by Healthwise; finally, both Drugs.com and GenieMD use the same algorithm developed by Harvard

Health Publications. After these exclusions, we evaluated 20 symptom checkers between June 2014 and

December 2014.

Symptom checkers’ characteristics

We categorized symptom checkers by whether they facilitated self-diagnosis, self-triage, or both; type of

organization that operated the symptom checker; the maximum number of diagnoses provided, and

whether they were based on Schmitt or Thompson nurse triage guidelines, which are decision support

protocols commonly used in telephone triage for pediatric and adult consultations, respectively.19 20

We

grouped government and health plans together because both have a financial incentive to deter

unnecessary visits. To estimate the number of visitors to symptom checkers, we used Compete Pro, a

US-based online marketing analysis website. 21

We obtained the number of unique visitors for October

2014. Visit data was not available for symptom checkers that were a part of a larger website (e.g.

mayoclinic.org), in certain countries, or those that were only provided as an app.

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Clinical vignettes

To evaluate symptom checkers’ diagnosis and triage performance, we used 45 SP vignettes. We

developed SP vignettes from various sources listed in the appendix, and the correct diagnosis was

provided by the SP vignette. We chose to use clinical vignettes to test performance because they are a

common method to test physicians on their diagnostic ability and management decisions. Though we

focused on more common problems, we purposefully included three rare, serious conditions (Rocky

Mountain spotted fever, tetanus, and malaria) to assess the tools’ ability for diagnosing and triaging

such problems.

Symptom checkers ask users for a list of symptoms or ask a series of questions. Each SP vignette was

simplified into a core set of symptoms for easy entry. In some situations, we supplemented the data

provided by the vignette because a symptom checker asked about a symptom not addressed in vignette.

We used the same set of symptoms, with additions, noted in the appendix for each symptom checker.

We stratified SP vignettes into 3 levels of severity: (1) 15 SP vignettes for which emergent care is

required, (2) 15 SP vignettes for which non-emergent care is reasonable, and (3) 15 SP vignettes for

which a medical visit is generally unnecessary and self-care is sufficient. Categorization of SP vignette

severity was based on consensus clinical judgment from three physicians on the research team.

Assessing diagnosis and triage results

Each SP vignette was entered into each website, and we recorded the resulting diagnoses and triage

advice. In some cases, we could not evaluate a vignette because some symptom checkers only focus on

children or adults or the symptom checker did not list or ask for the key symptom in vignette. We

referred to SP vignettes that successfully yielded an output as “SP evaluations”.

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To assess diagnostic accuracy, we noted whether the correct diagnosis was listed first or listed at all. For

several vignettes two symptom checkers presented a large number of diagnoses (up to 99). Because

such a long list of potential diagnoses is unlikely to be useful for a patient, we considered a diagnosis to

be listed at all only if it was within the first 20 diagnoses a symptom checker provided. We also judged

the diagnosis incorrect if the symptom checker indicated that the condition could not be identified. In a

sensitivity analysis, we limited our assessment of accuracy to the first 3 diagnoses instead of the first

diagnosis listed.

We categorized the triage advice into three groups: (1) Emergent, which included advice to call an

ambulance, go to the accident & emergency department, or see your GP immediately; (2) Non-

Emergent, which included advice to go to an urgent care facility, to call your GP, to see your GP, go to a

specialist, go to a retail clinic, or have an e-visit; and (3) Self-Care, which included advice to stay at home

or go to a pharmacy. If multiple triage locations were suggested (e.g. accident & emergency department

or a specialist), the most urgent suggestion was used. We chose to do so because in almost all of the

cases, the most urgent triage suggestion was listed first. Symptom checkers that required users to select

the correct diagnosis before giving triage advice were not included in assessing triage accuracy with the

exception of iTriage, which always suggested emergent triage advice.

Analysis

We calculated summary statistics for diagnostic accuracy and triage advice with 95% confidence

intervals based on binomial distribution using Stata/MP 13.0. Given our focus on symptom checkers as a

whole, we did not make statistical comparisons of accuracy between symptom checkers. We used chi-

square tests to compare the diagnosis and triage accuracy by level and urgency and by type of symptom

checker. We conducted a sensitivity analysis of triage advice excluding several symptom checkers that

always or usually recommended emergent care.

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Results

Study sample

The 20 identified symptom checkers were based in the United Kingdom, United States, Netherlands, and

Poland (Table 1). Ten of the symptom checkers provided both diagnoses and triage advice, 6 provided

only diagnoses, and 4 provided only triage advice. Performance was assessed on a total of 650 SP

evaluations for diagnosis and 516 SP evaluations for triage. Across the symptom checkers, 8 did not ask

for demographics (age and gender). For the 8 symptom checkers where we could estimate web traffic,

there were on average 1.25 million visitors in October 2014.

Accuracy of diagnosis being listed first

Overall, the correct diagnosis was listed first in 33% (95% CI 30-37; table 2 and 4) of SP evaluations.

Performance varied by urgency of condition. The correct diagnosis was listed first for 25% (95% CI 19-31)

of emergent SP evaluations and 39% (95% CI 32-45, p=0.004) of self-care SP evaluations (table 4). In a

sensitivity analysis, we found that the symptom checkers listed the correct diagnosis within the first

three diagnoses listed in 52% (95% CI 48-56) of SP evaluations.

Performance varied across symptom checkers and by urgency of vignettes (table 3). Listing the correct

diagnosis first ranged from 5% for MEDoctor (95% CI 0-13) of SP evaluations to 47% for Family Doctor

(95% CI 31-62).

Few differences were observed by symptom checker characteristics (table 5). There was no difference

between symptom checkers that did and did not ask for demographic information (34% [95% CI 29-39]

vs. 33% [95% CI 27-38], p=0.72).

Accuracy of listing correct diagnosis at all

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Across all symptom checkers, the correct diagnosis was listed in 60% (95% CI 56-63) of SP evaluations

(table 4). This varied by urgency of SP vignettes 52% (95% CI 45-59) for emergent conditions, 62% (95%

CI 55 to 68) for non-emergent conditions, and 65% (95% CI 59-72) for self-care conditions (p=0.013). The

correct diagnosis was listed at all in 63% (95% CI 60-67) of the common vignettes versus 19% (95% CI 9-

29) for the three rare conditions (p<0.001). There was no significant difference in listing the correct

diagnosis between symptom checkers that listed more than 11 diagnoses versus those that only listed 1-

3 diagnoses (4% [95% CI 57-70] vs. 54% [95% CI 47-61], p=0.15; table 5]. The accuracy of listing the

correct diagnosis by individual symptom checkers ranged from 34% (95% CI 17-52) to 84% (95% CI 73-

95) (table 3).

Accuracy of triage advice

Appropriate triage advice was given in 56% (95% CI 52-61) of SP evaluations and was higher for

emergent care vignettes versus those for which no medical care was necessary (80% [95% CI 74-86] vs.

34% [95% CI 27-41], p<0.001) (table 4). iTriage, Isabel, and Healthwise advised emergent care for 100%

of emergent SP evaluations. iTriage, Symcat, Symptomate and Isabel always suggested users to seek

care and therefore never advised self-care (table 3). Even when excluding these symptom checkers,

there was minimal improvement in the appropriateness of the other tools’ triage advice (61% [95% CI 56

to 66]).

Symptom checkers that used the Schmitt or Thompson nurse-triage protocols were more likely to

provide appropriate triage decisions than those that did not (72% [95% CI 60-84] vs. 55% [95% CI 50-59]

of SP evaluations, p=0.01). Accurate triage advice varied by operator (provider groups and physician

associations 68% [95% CI 58-77], private companies 59% [95% CI 53-65], health plans/governments 43%

[95% CI 34-51], p<0.001).

Discussion

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Using SP vignettes, we audited the performance of symptom checkers for self-diagnosis and triage.

Although there was a range of performance across symptom checkers, symptom checkers had clear

deficits in diagnosis and triage accuracy. On average symptom checkers listed the correct diagnosis in

60% of SP evaluations with the best-performing symptom checker listing the correct diagnosis in 84% of

SP evaluations. Our results on diagnostic are roughly similar to work that has focused on a more limited

set of diagnoses and just one symptom checker. A single orthopedic symptom checker listed the correct

diagnosis for knee pain 89% of the time and Boots WebMD listed the correct diagnosis 70% of the time

for ear, nose, and throat symptoms.22 23

In terms of triage, symptom checkers advised the appropriate

level of care about half the time, but this varied by clinical severity. The correct triage decision was more

than two times higher for SP vignettes requiring emergent care (80%) versus those SP vignettes where

no medical care was necessary (34%).

Whether this level of performance for diagnosis and triage is acceptable depends on what is viewed as

the gold standard. Physicians generally have a diagnostic error rate of 10-15% .24

If symptom checkers

are seen as a replacement for seeing a physician, their performance is clearly an inferior alternative.

A more appropriate comparison may be to compare symptom checkers to nurse telephone triage lines,

which are widely used in developed nations. The key component of symptom checkers may be

appropriate triage, as distinguishing between Rocky Mountain spotted fever and meningitis may be less

important than ensuring patients seek emergent care. Telephone triage recommendations, compared to

in-person physician recommendations, range in accuracy from 61% in a study of pediatric abdominal

pain to 69% in a multicenter observational study.25 26

Many nurse phone triage lines use the same

symptom checkers evaluated in this study and the Schmitt and Thompson telephone protocols were the

underlying logic for several symptom checkers.27

Symptom checkers may thus be viewed in general as a

reasonable alternative to telephone triage.

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One potential advantage of symptom checkers over telephone triage is cost. Telephone triage has been

promoted as a means of reducing unnecessary office visits.8 9 28 29

However, in a recent large cluster

randomized trial in 42 practices in four centres in the UK, telephone triage did not decrease spending, as

the savings from deterring visits was offset by the labor costs of nurse or physician time to respond to

the telephone calls.10

Because of their negligible costs, symptom checkers could potentially be a more

cost-effective way of providing triage advice—particularly if they can deter unnecessary office visits.

The risk-averse nature of symptom checker advice is a concern. In two-thirds of SP evaluations where

medical attention was not necessary, symptom checkers encouraged care. Four of the symptom

checkers never advised the user that medical attention was not necessary. This is consistent with prior

work where computer-based triage tools have been observed to provide more conservative triage

advice than physician consultations.30

This trend is also found in telephone triage, in which more

conservative triage recommendations has been attributed to organizational reasons and uncertainty

about the patient’s diagnosis.25

This risk-averse approach of symptom checkers may be

overcompensation for the lack of face-to-face care or driven by liability concerns. Some patients

researching health conditions are motivated by fear, and the listing of concerning diagnoses by

symptom checkers and risk-averse triage advice could contribute to hypochondriasis.31-33

The term

“cyberchondria” describes the escalated anxiety associated with self-diagnosis on the internet.34

The symptom checkers in this study represent the first generation of such tools, and there are a number

of potential advancements that may improve their performance in future versions. Incorporating local

epidemiological data may help inform diagnoses. For instance, addition of real-time information about

the local incidence of illness in the community greatly improved the performance of a Group A

Streptococcal pharyngitis diagnostic tool.35

Diagnosis and triage rates could also be improved if

symptom checkers could incorporate population or individual clinical data from medical claims or the

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electronic medical record. Demographic information is critical for both diagnostic and triage decisions

for programs like symptom checkers.36

One surprising finding in our study was that symptom checkers

that asked for demographic background information did not perform better. However, it is possible that

this demographic information was not effectively incorporated into the symptom checkers algorithms.

There were key limitations to this study. We cannot be sure we identified all publicly-available symptom

checkers, despite a thorough search including consultation with experts in this field and a search of all

relevant databases. We used clinical vignettes in which the symptoms and diagnoses were typically

clear, and few had comorbid conditions, resulting in a possible overestimation of the true diagnostic

accuracy of symptom checkers.24

When symptom checkers suggested several care sites (e.g. accident &

emergency department or GP office), our triage assessment was based only on the highest acuity site of

care listed and this may contribute to our finding that triage advice is risk-averse. Symptom checkers’

impact will depend on how patients respond to the triage advice, which will need to be evaluated in

future work.

Symptom checkers are part of a larger trend of both patients and physicians using the internet for many

health care tasks and therefore it appears likely that the use of symptom checkers will only increase.

Patients are chatting online with a physicians,37

emailing doctors for medical advice,38

receiving care via

e-visits,39 40

and downloading health apps to smartphones.41

From a physician’s perspective, an

increasing number of their patients are using new internet-based tools like symptom checkers and

physicians should be aware that the diagnosis and triage advice patients receive may often be

inaccurate. For patients, our results imply that in many cases, symptom checkers can give a sense of

possible diagnoses, but they should be cautious as there is a significant rate of diagnostic error and

tendency towards risk aversion. However, if the alternative to using a symptom checker is not seeking

any advice, there may be value in their use. Further evaluations and monitoring of symptom checkers

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will be important to assess whether they help users learn more and make better decisions about their

health.

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decision support for callers facing values-sensitive decisions: A mixed methods study.

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30. Richards D, Meakins J, Tawfik J, Godfrey L, Dutton E, Richardson G, et al. Nurse telephone triage for

same day appointments in general practice: multiple interrupted time series trial of effect on

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31. Poote A, French D, Dale J, Powell J. A study of automated self-assessment in primary care student

health centre setting. Journal of Telemedicine and Telecare 2014;20(3):125.

32. Usborne S. Cyberchondria: The perils of internet self-diagnosis. London: The Independent, February

17, 2009.

33. Hartzband P, Groopman J. Untangling the web - Patients, doctors, and the internet. New England

Journal of Medicine 2010;362(12):1064.

34. Brigo F, Igwe SC, Ausserer H, Nardone R, Tezzon F, Bongiovanni LG, et al. Why do people Google

epilepsy? An infodemiological study of online behavior for epilepsy-related search terms.

Epilepsy Behav 2014;31:67-70.

35. White RW, Horvitz E. Experiences with web search on medical concerns and self diagnosis. AMIA

Annu Symp Proc 2009;2009:696-700.

36. Fine AM, Nizet V, Mandl KD. Participatory medicine: A home score for streptococcal pharyngitis

enabled by real-time biosurveillance: a cohort study. Ann Intern Med 2013;159(9):577-83.

37. DocBot: A novel clinical decision support algorithm. Engineering in Medicine and Biology Society

(EMBC), 2014 36th Annual International Conference of the IEEE; 2014 26-30 Aug. 2014.

38. Eminovic N, Wyatt J, Tarpey A, Murray G, Ingram G. First evaluation of the NHS Direct Online Clinical

Enquiry Service: A nurse-led web chat triage service for the public. Journal of Medical Internet

Research 2004;6(2).

39. Eysenbach G, Diepgen T. Patients looking for information on the internet and seeking teleadvice.

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40. Mehrotra A, Paone S, Martich GD, Albert SM, Shevchik GJ. A comparison of care at e-visits and

physician office visits for sinusitis and urinary tract infection. JAMA Intern Med 2013;173(1):72-

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41. DeJong C, Santa J, Dudley RA. Websites that offer care over the Internet: is there an access quality

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Symptom

Checker Description

Maximum

No. of

Diagnoses

Observed

Triage Options Provided

AskMD (USA) Online health and wellness platform from

Sharecare

(https://www.sharecare.com/askmd/get-

started)

15 n/a

Drugs.com

(USA)

Online resource for drug and related health

information; uses content from Harvard

Health Publications

(http://www.drugs.com/symptom-

checker/)

10 ED, primary care doctor, home care

EarlyDoc

(Netherlands)

For triage criteria, uses Dutch College of

General Practitioners (NHG) TriageWijzer

and the Australian Triage Scale (used in

Australia and New Zealand to assess

urgency). (https://www.earlydoc.com/en/)

3 Don't wait and call a doctor now,

call a doctor preferably today, see

your doctor preferably on a

weekday, your complaints don't

seem urgent

Esagil (USA) Provides list of likely diagnoses (based on

the percent of entered symptoms that are

congruent with the diagnosis); the user can

also enter blood and urine analysis results

along with symptoms (http://esagil.org/)

65 n/a

Family Doctor

(USA)

Displays flow chart to track symptoms to a

diagnosis and triage option; produced by

the American Academy of Physicians

(http://familydoctor.org/familydoctor/en/h

ealth-tools/search-by-symptom.html)

7 ER, see your doctor, home care

FreeMD (USA) Takes user through a series of questions in a

"checkup" to finish with "what might be

wrong with you" and "where to go for

care"; owned by DSHI Systems, which

provides triage decision support solutions

from emergency medicine physicians to the

US government (Dep. of Veteran Affairs)

and private sector companies; program

called TriageXpert

(http://www.freemd.com/)

3 ED, urgent care, doctor's office,

doctor e-visit, retail clinic, dentist,

home care

Harvard

Medical School

Family Health

Guide (USA)

From Harvard Health Publications; this tool

is available both online and in print

(published 1999), and the online tool often

refers the user to the book in order to make

a diagnosis and triage decision

(http://www.health.harvard.edu/fhg/sympt

oms/symptoms.shtml)

4 ED, GP, home care

Healthline

(USA)

Health and wellness website that licenses

content to employers, health providers, and

health plans

(http://www.healthline.com/symptom-

checker)

76 n/a

Healthwise Non-profit provider for health content and n/a Call 911 now, seek care now, seek

Table 1|Overview of symptom checkers included in the study

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18

(USA) patient education; symptom checker

licensed to other organizations; we

accessed using the Province of Alberta's

website

(https://myhealth.alberta.ca/health/pages/

symptom-checker.aspx)

care today, try home care

Healthy

Children (USA)

From the American Academy of Pediatrics;

use's Barton D. Schmitt's "Pediatric

HouseCalls Symptom Checker" triage

protocol

(http://www.healthychildren.org/English/ti

ps-tools/symptom-

checker/Pages/default.aspx)

n/a Call 911 now, call your doctor now

(night or day), call your doctor

within 24 hours, call your doctor

during weekday office hours, parent

care at home

Isabel (UK) Created by the Isabel Medical Charity

(http://symptomchecker.isabelhealthcare.c

om/suggest_diagnoses_advanced/landing_

page)

10 Walk in care, family doctor,

emergency services

iTriage (USA) Owned by Aetna; provides clinical sites in

user's region with addresses and phone

numbers (https://www.itriagehealth.com/)

5 Emergency department, urgent

care, retail clinic, family practice,

internal medicine, specialties,

prescription medication, over the

counter medication

Mayo Clinic

(USA)

Health resource website from Mayo Clinic

(http://www.mayoclinic.org/symptom-

checker/select-symptom/itt-20009075)

20 n/a

MEDoctor

(USA)

Free differential diagnosis system from

MEDoctor, Inc.

(https://www.medoctor.com/)

3 n/a

NHS Symptom

Checkers (UK)

Available through England's National Health

Services (NHS) Choices website

(https://www.nhs.uk/symptomcheckers/pa

ges/symptoms.aspx)

n/a Emergency department, general

practitioner, home care

Symcat (USA) Triage tool uses data linking specific patient

symptoms and physician diagnoses across

visits seen in the NAMCS survey

(http://www.symcat.com/)

6 Primary care, retail clinic,

emergency room, urgent care

Symptify (USA) Online self-assessment tool and other

health services including emergency contact

list, consultation list etc.

(https://symptify.com/)

9 ER, urgent care, home care,

inconclusive

Symptom MD

(USA)

iPhone and Android app, provides symptom

care guides from Barton D. Schmitt's

pediatric telephone triage guidelines and

David A. Thompson's adult telephone triage

guidelines (http://www.symptommd.com/)

n/a Call 911 now, go to ER now, Call

doctor now or go to ER, Call doctor

within 24 hours, Call doctor during

office hours, self-care at home

Symptomate

(Poland)

Uses Bayesian network methodology and a

medical database for diagnoses

(https://symptomate.com/)

5 ER, specialist, GP

WebMD (USA) Medical reference and health care resource

website

(http://symptoms.webmd.com/#introView)

99 n/a

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Confidential: For Review Only

19

Ask

MD

/

Sh

are

care

Dru

gs.

com

Earl

yD

oc

Esa

gil

Fam

ily D

oct

or

Fre

eM

D

HM

S F

am

ily H

ealt

h G

uid

e

He

alt

hli

ne

Isab

el

iTri

age

Mayo

Cli

nic

MED

oct

or

Sym

cat

Sym

pti

fy

Sym

pto

mate

We

bM

D

Dru

gs.

com

Earl

yD

oc

Fam

ily D

oct

or

Fre

eM

D

HM

S F

am

ily H

ealt

h G

uid

e

He

alt

hw

ise

He

alt

hy C

hil

dre

n

Isab

el

iTri

age

NH

S

Sym

cat

Sym

pti

fy

Sym

pto

mate

Sym

pto

mM

D

Standardized Patient Vignette Emergent Care Non Emergent Care Self Care

Require emergent care

Acute liver failure 〇〇〇〇 U

Appendicitis 〇〇 ⊗ ⊗ ⊗ ⊗ ⊗ 〇〇 ⊗ ⊗ ▨Asthma attack ⊗ ⊗ ⊗ ⊗ 〇 ⊗ 〇 ⊗ ⊗ 〇 ⊗ 〇

COPD more severe 〇 ⊗ 〇 ⊗ 〇 ▨Deep Vein Thrombosis ⊗ ⊗ ⊗ ⊗ 〇〇〇 ⊗ ⊗

Heart attack ⊗ ⊗ ⊗ ⊗ ⊗ ⊗

Hemolytic Uremic Syndrome ⊗ 〇〇 U

Kidney Stones 〇 ⊗ ⊗ ⊗ ⊗ ⊗ ⊗ 〇〇〇 ▨Malaria 〇〇 N N

Meningitis ⊗ ⊗ ⊗ ⊗ ⊗

Pneumonia (more severe) ⊗ 〇〇〇 ⊗ 〇〇〇〇 ⊗ ▨Pulmonary Embolism ⊗ 〇 ⊗ 〇〇 ⊗ 〇 ⊗ ⊗ ▨Rocky Mountain Spotted

Fever⊗

Stroke 〇 ⊗ ⊗ 〇〇 ▨Tetanus ⊗

Symptom Checker

Incorrect

diagnosis

Correct

diangosis

listed

Correct

diagnosis

listed first

Process couldn't be

started (ex. Too young)

Diagnosis given Triage Advice Given

Table 2|Diagnosis given and triage advice from each symptom checker, stratified by severity of the standardized patient (SP) vignette

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20

Ask

MD

/

Sh

are

care

Dru

gs.

com

Ea

rly

Do

c

Esa

gil

Fa

mil

y D

oct

or

Fre

eM

D

HM

S F

am

ily

He

alt

h G

uid

e

He

alt

hli

ne

Isa

be

l

iTri

ag

e

Ma

yo

Cli

nic

ME

Do

cto

r

Sy

mca

t

Sy

mp

tify

Sy

mp

tom

ate

We

bM

D

Dru

gs.

com

Ea

rly

Do

c

Fa

mil

y D

oct

or

Fre

eM

D

HM

S F

am

ily

He

alt

h G

uid

e

He

alt

hw

ise

He

alt

hy

Ch

ild

ren

Isa

be

l

iTri

ag

e

NH

S

Sy

mca

t

Sy

mp

tify

Sy

mp

tom

ate

Sy

mp

tom

MD

Symptom Checker

Requires non-emergent care

Acute otitis media ⊗ ⊗ ⊗ ⊗ ⊗ ⊗ ⊗ ▩Potential bacterial

pharyngitisa

〇 ⊗ ⊗ ⊗ 〇〇 ⊗ 〇 ⊗ ⊗ ▩Potential bacterial

pharyngitisa

⊗ ⊗ ⊗ ⊗ ⊗ 〇 ⊗ ⊗ ⊗ 〇 ⊗ ⊗ N

Acute sinusitis 〇〇 ⊗ ⊗ ⊗ ⊗ 〇〇〇 ⊗ ⊗ ▩Back pain with foot drop ⊗ ⊗ ⊗ 〇 ⊗ ▨Cellulitis ⊗ 〇〇

COPD flare ⊗ ⊗ ⊗ ⊗ 〇〇 ▨Influenza ⊗ ⊗ ⊗ 〇 ⊗ ⊗ ⊗ 〇〇 ⊗ ⊗ ▨Mononucleosis ⊗ 〇〇 ⊗ 〇〇〇 ⊗ ⊗ ▩Peptic Ulcer Disease 〇〇 ⊗ ⊗ 〇〇 ⊗ ⊗ 〇 ⊗ ⊗ N

Pneumonia ⊗ 〇〇 ⊗ ⊗ 〇〇 ⊗ ▩Salmonella ⊗ 〇 ▩Shingles 〇 ⊗ ⊗ ⊗ 〇 ⊗ 〇〇 ⊗ N

Urinary tract infection 〇 ⊗ ⊗ ⊗ ⊗ ⊗ 〇 ⊗ ⊗ ⊗ ⊗ ⊗ ▩Vertigo ⊗ 〇 ⊗ ⊗ ⊗ N

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21

Abbreviations: HMS, Harvard Medical School; NHS, National Health Services a There are multiple vignettes for this condition. See the Appendix for each.

Ask

MD

/

Sh

are

care

Dru

gs.

com

Ea

rly

Do

c

Esa

gil

Fa

mil

y D

oct

or

Fre

eM

D

HM

S F

am

ily

He

alt

h G

uid

e

He

alt

hli

ne

Isa

be

l

iTri

ag

e

Ma

yo

Cli

nic

ME

Do

cto

r

Sy

mca

t

Sy

mp

tify

Sy

mp

tom

ate

We

bM

D

Dru

gs.

com

Ea

rly

Do

c

Fa

mil

y D

oct

or

Fre

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D

HM

S F

am

ily

He

alt

h G

uid

e

He

alt

hw

ise

He

alt

hy

Ch

ild

ren

Isa

be

l

iTri

ag

e

NH

S

Sy

mca

t

Sy

mp

tify

Sy

mp

tom

ate

Sy

mp

tom

MD

Symptom Checker

Self-Care Appropriate

Acute bronchitisa 〇〇 ⊗ ⊗ 〇〇 ▧

Acute bronchitisa 〇〇 ⊗ ⊗ ⊗ 〇〇 ⊗ 〇 ⊗ ⊗ N

Acute conjunctivitis ⊗ ⊗ ⊗ ⊗ ⊗ ⊗ ◯ ◯ ◯ ⊗ ⊗ ▨Acute viral pharyngitis 〇 ⊗ ⊗ 〇〇 ⊗ ⊗ ⊗ ⊗ ▧Allergic rhinitis ⊗ 〇 ⊗ ⊗ ⊗ 〇 ⊗ ⊗ ⊗ ⊗ ⊗ 〇 ⊗ ▧Back pain, unremarkable ⊗ ⊗ ⊗ ⊗ ⊗ ⊗ ⊗ 〇 ⊗ ⊗ ⊗ 〇 ▧Bee sting without anaphylaxis 〇 ⊗ 〇 ⊗

Candidal yeast infection ⊗ ⊗ ⊗ ⊗ ⊗ ⊗ ⊗ ⊗ ⊗ ⊗ 〇 ⊗ ▩Canker sore 〇 ⊗ 〇〇〇

Constipation ⊗ ⊗ ⊗ ⊗ ⊗ N U

Eczema ⊗ 〇〇〇 ⊗ ⊗ ⊗ ⊗ 〇 H

Stye 〇 ⊗ ⊗ 〇〇 ⊗ 〇〇 ▧Viral URI

a 〇 ⊗ ⊗ ⊗ ◯ ◯ ⊗ ◯ 〇〇 ⊗ 〇〇 ▧Viral URI

a ⊗ 〇 ⊗ ⊗ 〇〇〇〇〇 ▧Vomiting ⊗ 〇 ⊗ 〇〇 ⊗ ⊗ 〇 ⊗ N N

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% (95% CI)

Symptom Checker

(n=20)

Correct

Diagnosis

Listed First

Correct

Diagnosis

Listed

Appropriate

Triage

Ask MD 43 (26-59) 75 (61-89) - b

Drugs.com 40 (24-55) 58 (43-74) 60 (44-75)

EarlyDoc 32 (9-55) 37 (13-61) 53 (26-79)

Esagil 20 (8-33) 50 (35-65) - b

Family Doctor 47 (31-62) 56 (40-71) 54 (38-70)

FreeMD 36 (22-51) 48 (32-63) 59 (44-74)

HMS Family Health

Guide

34 (18-50) 55 (39-72) 78 (64-91)

Healthline 38 (23-53) 58 (43-73) - b

Healthwise - a -

a 43 (28-58)

Healthy Children - a -

a 73 (48-99)

Isabel 44 (29-60) 84 (73-95) 51 (36-66)

iTriage 36 (22-51) 77 (64-90) 33 (19-48)

Mayo Clinic 17 (5-29) 76 (62-89) - b

MEDoctor 5 (0-13) 43 (26-60) - b

NHS - a -

a 52 (37-68)

Symcat 40 (25-55) 76 (62-89) 44 (29-60)

Symptify 29 (15-43) 44 (29-60) 70 (55-85)

Symptomate 31 (14-48) 34 (17-52) 64 (36-93)

SymptomMD - a -

a 71 (57-86)

WebMD 36 (21-50) 62 (47-77) - b

Table 3|Accuracy of diagnosis decision and triage advice for each symptom

checker

Abbreviations: HMS, Harvard Medical School; NHS, National Health Services a Symptom checker does not provide diagnosis suggestions

b Symptom checker does not provide triage advice

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23

% (95% CI)

No. of

vignettes

(%)

Correct Diagnosis

Listed First P value

Correct

Diagnosis

Listed

P value Appropriate

Triage P value

All Vignettes 45 (100) 33 (30-37) 60 (56-63) 56 (52-61)

Type of SP vignette

Emergent 15 (33) 25 (19-31)

0.004

52 (45-59)

0.013

80 (74-86)

< 0.001 Non-emergent 15 (33) 37 (30-43) 62 (55-68) 55 (47-62)

Self-care 15 (33) 39 (32-45) 65 (59-72) 34 (27-41)

Table 4|Accuracy of diagnosis decision and triage advice for all symptom checkers, stratified by severity of the SP vignette and by

frequency of the condition

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24

No. (%)

% (95% CI)

% (95% CI)

No. (%)

% (95% CI)

All Symptom

Checkers

Symptom

Checkers

that

Diagnose

Correct

Diagnosis

Listed First

P value

Correct

Diagnosis

Listed

P value

Symptom

checkers

that provide

triage

advice

Appropriate

Triage P value

All Symptom

Checkers 20 (100) 16 (100)

33 (30-37)

60 (56-63)

14 (100)

56 (52-61)

Use nurse-triage books (Schmitt or Thompson)?

Yes 3 (15) 0 (0)

- a

- a

- a

- a

12 (86)

72 (60-84) 0.01

No 17 (85) 16 (100)

33 (30-37) 60 (56-63) 2 (14)

55 (50-59)

Asks demographic questions?

Yes 11 (55) 9 (56)

34 (29-39) 0.72

62 (57-66) 0.26

8 (57)

51 (45-56) 0.001

No 9 (45) 7 (44)

33 (27-38) 57 (51-63) 6 (43)

65 (59-72)

Site owner

Health plan or

government 3 (15) 1 (6)

36 (22-51)

0.9

77 (64-90)

0.02

3 (21)

43 (34-51)

< 0.001 Provider group 5 (25) 4 (25)

34 (26-41) 62 (55-70) 3 (21)

68 (58-77)

Private company 12 (60) 11 (69)

33 (29-37) 57 (52-62) 8 (57)

59 (53-65)

Maximum number of diagnoses listed

1-3 5 (25) 5 (25)

33 (26-40)

0.48

54 (47-61)

0.15

4 (29)

52 (44-60)

0.25 4-10 6 (30) 6 (30)

36 (30-42) 60 (54-66) 6 (43)

58 (52-65)

11+ 5 (25) 5 (25)

31 (24-37) 64 (57-70) 4 (29)

- b

Table 5|Accuracy of diagnosis given and triage advice for all symptom checkers given certain characteristics of the tools

a Symptom checker does not provide diagnosis suggestions

b Symptom checker does not provide triage advice

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nlyAppendix

This appendix includes more details on the standardize patient (SP) vignettes that were used,

diagnosis and triage accuracy for each symptom checker, and the results of our sensitivity

analyses.

Our SP vignettes were gathered from several sources, which are listed in Supplemental Table 1.

Each vignette provided the age, gender, symptoms, and correct diagnosis for a given condition.

This table also notes where we added additional symptoms if the symptom checkers asked for

them. Added symptoms are italicized. The “simplified” symptoms were those inputted into

each symptom checker.

Supplemental Table 2 has additional information for Table 3 in the manuscript. This includes

the accuracy of the diagnosis decision and triage advice for each symptom checker with the

addition of the stratification by the severity of the SP vignette.

Lastly, we performed sensitivity analyses shown in Supplemental Table 3 to assess the

appropriateness of the triage advice of the symptom checkers by excluding certain symptom

checkers that were not as variable in their triage advice. This includes iTriage, which always

suggested that the user visit an emergency department, and Symcat, Symptomate, and Isabel,

all of which never suggest self-care. Excluding these symptom checkers only had a modest

impact on rates of appropriate triage advice.

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Diagnosis Vignette Simplified (added symptoms)

Acute liver failure¹ A 48-year-old woman with a history of migraine headaches presents to the emergency room with altered mental

status over the last several hours. She was found by her husband, earlier in the day, to be acutely disoriented and

increasingly somnolent. On physical examination, she has scleral icterus, mild right upper quadrant tenderness, and

asterixis. Preliminary laboratory studies are notable for a serum ALT of 6498 units/L, total bilirubin of 5.6 mg/dL, and

INR of 6.8. Her husband reports that she has consistently been taking pain medications and started taking additional

500 mg acetaminophen pills several days ago for lower back pain. Further history reveals a medication list with

multiple acetaminophen-containing preparations.

48 y/o f, confusion,

disorientation, increasingly

drowsy, mild right upper

quadrant tenderness, chronic

tylenol/acetaminophen -

recently took more

Appendicitis¹ A 12-year-old girl presents with sudden-onset severe generalized abdominal pain associated with nausea, vomiting,

and diarrhea. On exam she appears ill and has a temperature of 104°F (40°C). Her abdomen is tense with generalized

tenderness and guarding. No bowel sounds are present.

12 y/o f, sudden onset severe

abdominal pain, nausea,

vomiting, diarrhea, T=104

Asthma¹ A 27-year-old woman with a history of moderate persistent asthma presents to the emergency room with

progressive worsening of shortness of breath, wheezing, and cough over 3 days. She reports prior exposure to a

person who had a runny nose and a hacking cough. She did not receive significant relief from her rescue inhaler with

worsening symptoms, despite increased use. She has been compliant with her maintenance asthma regimen, which

consists of an inhaled corticosteroid and a leukotriene receptor antagonist for maintenance therapy and albuterol as

rescue therapy. Her cough is disrupting her sleep pattern and as a consequence she is experiencing daytime

somnolence, which is affecting her job performance.

27 y/o f, Hx of asthma, mild

shortness of breath,

wheezing, 3 days cough,

symptoms not responsive to

inhalers, recent cold

COPD flare (more severe)¹A 67-year-old woman with a history of COPD presents with 3 days of worsening dyspnea and increased frequency

of coughing. Her cough is now productive of green, purulent sputum. The patient has a 100-pack-year history of

smoking. She has had intermittent, low-grade fever of 100°F (37.7°C) for the past 3 days and her appetite is poor.

She has required increased use of rescue bronchodilator therapy in addition to her maintenance medications to

control symptoms.

67 y/o f, Hx of COPD, 3 days

worsening shortness of

breath, increase coughing,

green sputum, low grade

fever, increase use of rescue

bronchodilator therapy

Deep vein

thrombosis¹

A 65-year-old woman presents with unilateral leg pain and swelling of 5 days' duration. There is a history of

hypertension, mild CHF, and recent hospitalization for pneumonia. She had been recuperating at home but on

beginning to mobilize and walk, the right leg became painful, tender, and swollen. On examination, the right calf is 4

cm greater in circumference than the left when measured 10 cm below the tibial tuberosity. Superficial veins in the

leg are more dilated on the right foot and the right leg is slightly redder than the left. There is some tenderness on

palpation in the popliteal fossa behind the knee.

65 y/o f, 5 days swelling, pain

in one leg, recent

hospitalization, leg painful,

tender, swollen, red

Requires emergent care (n=15)

Supplemental Table 1: The 45 SP vignettes used to judge the symptom checkers’ accuracy and their condensed formats

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Heart Attack² Mr. Y is a 64 year old Chinese male who presents with chest pain for 24 hours. One day prior to presentation, the

patient began to experience 8/10, non-radiating substernal chest pressure associated with diaphoresis and

shortness of breath. The pain intially improved with Tylenol, however over the following 24 hours, his symptoms

worsened. The patient went to his primary physician, where an EKG was performed which showed ST elevation in

leads V2-V6.

64 y/o m, 1 day chest pain

(8/10), non-radiating

substernal chest pressure,

sweating, shortness of

breath, (chest tightness )

Hemolytic uremic

syndrome¹

A 4-year-old boy presents with a 7-day history of abdominal pain and watery diarrhea that became bloody after the

first day. Three days before the onset of symptoms, he had visited the county fair with his family and had eaten a

hamburger. Physical examination reveals a mild anemia

4 y/o m, 7 day Hx of

abdominal pain, bloody

diarrhea, ate hamburger at

fair 3 days ago

Kidney stones¹ A 45-year-old white man presents to the emergency department with a 1-hour history of sudden onset of left-sided

flank pain radiating down toward his groin. The patient is writhing in pain, which is unrelieved by position. He also

complains of nausea and vomiting.

45 y/o m, 1 hour severe left-

sided flank pain radiating into

groin, nausea, vomiting, pain

unrelieved by position

Malaria¹ A 28-year-old man presents to his physician with a 5-day history of fever, chills, and rigors, not improving with

acetaminophen (paracetamol), along with diarrhea. He had been traveling in Central America for 3 months,

returning 8 weeks ago. He had been bitten by mosquitoes on multiple occasions, and although he initially took

malaria prophylaxis, he discontinued it due to mild nausea. He does not know the specifics of his prophylactic

therapy. On examination he has a temperature of 100.4°F (38°C), and is mildly tachycardic with a BP of 126/82

mmHg. The remainder of the examination is normal.

28 y/o m, 5 day Hx of fever,

chills, rigors, diarrhea, recent

travel abroad to area with

malaria, bitten by

mosquitoes, did not take

malaria prophylaxis

consistently

Meningitis¹ An 18-year-old male student presents with severe headache and fever that he has had for 3 days. Examination

reveals fever, photophobia, and neck stiffness.

18 y/o m, 3 days severe

headache, fever,

photophobia, neck stiffness

Pneumonia³ A 65-year-old man with hypertension and degenerative joint disease presents to the emergency department with a

three-day history of a productive cough and fever. He has a temperature of 38.3°C (101°F), a blood pressure of

144/92 mm Hg, a respiratory rate of 22 breaths per minute, a heart rate of 90 beats per minute, and oxygen

saturation of 92 percent while breathing room air. Physical examination reveals only crackles and egophony in the

right lower lung field. The white-cell count is 14,000 per cubic millimeter, and the results of routine chemical tests

are normal. A chest radiograph shows an infiltrate in the right lower lobe.

65 y/o m, Hx of hypertension

and degenerative joint

disease, 3 day Hx of

productive cough and fever

(101)

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Pulmonary embolism A 65-year-old man presents to the emergency department with acute onset of SOB of 30

minutes' duration. Initially, he felt faint but did not lose consciousness. He is complaining of

left-sided chest pain that worsens on deep inspiration. He has no history of cardiopulmonary

disease. A week ago he underwent a total left hip replacement and, following discharge, was

on bed rest for 3 days due to poorly controlled pain. He subsequently noticed swelling in his

left calf, which is tender on examination. His current vital signs reveal a fever of 100.4°F

(38.0°C), heart rate 112 bpm, BP 95/65, and an O2 saturation on room air of 91%.

65 y/o m, shortness of

breath for 30 min,

chest pain that

worsens with

inspiration, recent

surgery, recent bed

rest, swelling in left

calf, which is tender,

fever

Pulmonary embolism. 2014;

https://online.epocrates.com/noFra

me/showPage?method=diseases&M

onographId=116&ActiveSectionId=22

. September 22, 2014.

Rocky Mountain

Spotted Fever

An 8-year-old boy in Oklahoma is brought to the emergency department over the fourth of July

weekend because of fever, chills, malaise, athralgias, and a headache. Physical examination

reveals a maculopapular rash that is most prominent on his wrists and ankles.

8 y/o m, Fever, chills,

joint pain, headache,

rash wrists/ankles

Plantz SH, Adler JN, eds. NMS

Emergency Medicine. Baltimore:

Williams & Wilkins; 1998. National

Medical Series for Independent

Study.

Stroke A 70-year-old man with a history of chronic HTN and atrial fibrillation is witnessed by a family

member to have nausea, vomiting, and right-sided weakness, as well as difficulty speaking and

comprehending language. The symptoms started with only mild slurred speech before

progressing over several minutes to severe aphasia and right arm paralysis. The patient is

taking warfarin.

70 y/o m, nausea,

vomiting, right-sided

weakness, rt arm

paralysis, difficulty

speaking and

comprehension

Hemorrhagic stroke. 2014;




2. September 24, 2014.

Tetanus A 63-year-old man sustained a cut on his hand while gardening. His immunization history is

significant for not having received a complete tetanus immunization schedule. He presents

with signs of generalized tetanus with trismus ("lock jaw"), which results in a grimace described

as "risus sardonicus" (sardonic smile). Intermittent tonic contraction of his skeletal muscles

causes intensely painful spasms, which last for minutes, during which he retains consciousness.

The spasms are triggered by external (noise, light, drafts, physical contact) or internal stimuli,

and as a result he is at the risk of sustaining fractures or developing rhabdomyolysis. The

tetanic spasms also produce opisthotonus, board-like abdominal wall rigidity, dysphagia, and

apneic periods due to contraction of the thoracic muscles and/or glottal or pharyngeal

muscles. During a generalized spasm the patient arches his back, extends his legs, flexes his

arms in abduction, and clenches his fists. Apnea results during some of the spasms. Autonomic

overactivity initially manifests as irritability, restlessness, sweating, and tachycardia. Several

days later this may present as hyperpyrexia, cardiac arrhythmias, labile hypertension, or

hypotension.

65 y/o m, cannot open

mouth, contraction of

muscles causing

painful spasms for

minutes, sweating,

tachycardia, cut hand

while gardening, did

not get tetanus shot

Tetanus infection. 2014;




. September 23, 2014.

Acute otitis media An 18-month-old toddler presents with 1 week of rhinorrhea, cough, and congestion. Her

parents report she is irritable, sleeping restlessly, and not eating well. Overnight she

developed a fever. She attends day care and both parents smoke. On examination signs are

found consistent with a viral respiratory infection including rhinorrhea and congestion. The

toddler appears irritable and apprehensive and has a fever. Otoscopy reveals a bulging,

erythematous tympanic membrane and absent landmarks.

18 mo f, 1 week

rhinorrhea, cough,

congestion, irritable,

lack of appetite, fever,

in daycare

Otitis media. 2014;



onographId=39&ActiveSectionId=22.

September 22, 2014.

Requires non-emergent care (n=15)

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Acute pharyngitis¹ A 7-year-old girl presents with abrupt onset of fever, nausea, vomiting, and sore throat. The child denies cough,

rhinorrhea, or nasal congestion. On physical exam, oral temperature is 101°F (38.5°C) and there is an exudative

pharyngitis, with enlarged cervical lymph nodes. A rapid antigen test is positive for group A Streptococcus (GAS).

7 y/o f, fever (101), nausea,

vomiting, sore throat, swollen

lymph nodes, tonsilar

exudate; no cough,

rhinorrhea, or nasal

congestion

Acute pharyngitis5 Mr. A is a 24 year-old man who presents to your office for complaints of sore throat, fever, and headache. His

symptoms started 2 days ago with acute onset of sore throat and fever to 102.2. He has had no cough. His physical

examination is normal, except for the presence of tonsillar exudates and some tender anterior cervical

lymphadenopathy. He is otherwise in good health, and is on no medications except for ibuprofen for fever. He has

no drug allergies. (, Centor score = 4 – treat, or test and treat)

24 y/o m, sore throat, fever

(102.2), headache, no

cough,tonsilar exudates

Acute sinusitis5 Mrs. S is a 35 year-old woman who presents with 15 days of nasal congestion. She has had facial pain and green

nasal discharge for the last 12 days. She has had no fever. On physical examination, she has no fever and the only

abnormal finding is maxillary tenderness on palpation. She is otherwise healthy, except for mild obesity. She is on no

medications, except for an over-the-counter decongestant. She has no drug allergies

35 y/o f, sx for 15 days, nasal

congestion, facial pain, green

nasal discharge, no fever

Back pain6 Consider a 35-year-old man who developed low back pain after shoveling snow 3 weeks ago. He presents to the

office for an evaluation. On examination there is a new left foot drop. In study 82% physicians recommend MRI

(sciatica/sprain)

35 y/o m, back pain following

shoveling, left foot drop,

symptoms 3 weeks of

duration (loss of sensation in

foot)

Cellulitis¹ A 45-year-old man presents with acute onset of pain and redness of the skin of his lower extremity. Low-grade fever

is present and the pretibial area is erythematous, edematous, and tender.

45 y/o m, pain and redness of

skin, low grade fever,

redness, edema, and

tenderness lower leg

COPD flare (milder)¹ A 56-year-old woman with a history of smoking presents to her primary care physician with shortness of breath and

cough for several days. Her symptoms began 3 days ago with rhinorrhea. She reports a chronic morning cough

productive of white sputum, which has increased over the past 2 days. She has had similar episodes each winter for

the past 4 years. She has smoked 1 to 2 packs of cigarettes per day for 40 years and continues to smoke. She denies

hemoptysis, chills, or weight loss and has not received any relief from over-the-counter cough preparations.

56 y/o f, Hx of smoking,

shortness of breath and

cough for several days,

rhinorrhea 3 days ago, white

sputum, no chills

Influenza¹ A 30-year-old woman presents in January with 2-day history of fever, cough, headache, and generalized weakness.

She was in her usual state of health before an abrupt onset of these symptoms. A few viral illnesses have affected

her during the current winter, but not to this severity. She reports sick contacts at work and did not receive the

seasonal influenza vaccine this season.

30 y/o f, 2 day fever, cough,

headache, weakness, did not

get flu shot

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Mononucleosis¹ A 16-year-old female high school student presents with complaints of fever, sore throat, and fatigue. She started

feeling sick 1 week ago. Her symptoms are gradually getting worse, and she has difficulty swallowing. She has had a

fever every day, and she could hardly get out of bed this morning. She does not remember being exposed to

anybody with a similar illness recently. On physical examination she is febrile and looks sick. Enlarged cervical lymph

nodes, exudative pharyngitis with soft palate petechiae and faint erythematous macular rash on the trunk and arms

are found.

16 y/o f, 1 week Hx of fever,

sore throat, fatigue, difficulty

swallowing, fever, enlarged

lymph nodes, exudates,

macular rash on trunk/arms

Peptic Ulcer Disease¹ A 40-year-old man presents to his primary care physician with a 2-month history of intermittent upper abdominal

pain. He describes the pain as a dull, gnawing ache. The pain sometimes wakes him at night, is relieved by food and

drinking milk, and is helped partially by ranitidine. He had a similar but milder episode about 5 years ago, which was

treated with omeprazole. Physical examination reveals a fit, apparently healthy man in no distress. The only

abnormal finding is mild epigastric tenderness on palpation of the abdomen.

40 y/o m, 2 month Hx of

intermittent upper abdominal

pain, dulling and gnawing

ache, wakes at night and is

relieved by food/drinking

milk/ranitidine, prior episode

5 yrs ago

Pneumonia¹ A 6-year-old boy with a medical history significant for mild persistent asthma is brought to the clinic by his mother

with a history of a 5-day cough. His mother reports that the child's fever continues to be elevated despite

acetaminophen therapy. He has missed school for the past 3 days and he has a classmate sick with pneumonia. The

mother reports that the appetite is good for the child. His cough produced yellowish sputum at home. His vitals at

the clinic are: respiratory rate 19 breaths/min, heart rate 80 beats/min, and temperature 101.6°F (38.7°C). He

appears in no respiratory distress. His lung examination reveals bilateral rales and occasional wheeze. CXR reveals

lobar infiltrates without pleural effusions.

6 y/o m, Hx of asthma, 5 days

cough, fever, appetite good,

yellow sputum, t 101.6

Salmonella¹ A 14-year-old boy presents with nausea, vomiting, and diarrhea. Eighteen hours earlier, he had been at a picnic

where he ingested undercooked chicken along with a variety of other foods. He reports moderate-volume,

nonbloody stools occurring 6 times a day. He has mild abdominal cramps and a low-grade fever. He is evaluated at

an acute care clinic and found to be mildly tachycardic (heart rate 105 bpm) with a normal BP and a low-grade

temperature of 100.1°F (37.8°C). His physical exam is unremarkable except for mild diffuse abdominal tenderness

and mild increased bowel sounds. He is able to take oral fluids and is instructed on the appropriate oral fluid and

electrolyte rehydration.

14 y/o m, nausea, vomiting,

non-bloody diarrhea, mild

abdominal cramps (T=100.1),

mild abdominal tenderness,

diarrhea after attending a

picnic and eating

undercooked chicken,

Shingles¹ A 77-year-old man reports a 5-day history of burning and aching pain on the right side of his chest. This is followed

by the development of erythema and a maculopapular rash in this painful area, accompanied by headache and

malaise. The rash progressed to develop clusters of clear vesicles for 3 to 5 days, evolving through stages of

pustulation, ulceration, and crusting.

77 y/o m, 5 day burning and

aching on right side of chest,

erythema, maculopapular

rash, headache, malaise, rash

progressed to clear vesicles

after 3-5 days

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Urinary tract

infection¹

A 26-year-old female newly wed presents complaining of painful urination, feeling of urgent need to urinate, and

more frequent urination for 2 days. She denies any fever, chills, nausea, vomiting, back pain, vaginal discharge, or

vaginal pruritus.

26 y/o f, painful urination,

urgent need to urinate, more

frequent urination for 2 days,

sexually active; no fever,

chills, nausea, vomiting, back

pain, vaginal discharge,

vaginal pruritus

Vertigo¹ A 65-year-old woman presents with a chief complaint of dizziness. She describes it as a sudden and severe spinning

sensation precipitated by rolling over in bed onto her right side. Symptoms typically last <30 seconds. They have

occurred nightly over the last month and occasionally during the day when she tilts her head back to look upward.

She describes no precipitating event prior to onset and no associated hearing loss, tinnitus, or other neurologic

symptoms. Otologic and neurologic examinations are normal except for the Dix-Hallpike maneuver, which is negative

on the left but strongly positive on the right side.

65 y/o f, dizziness, sudden

onset, recurrent, lasts <30

sec, consistent trigger, no

hearing loss, ringing in ears,

muscle weakness, loss of

sensation

Acute bronchitis¹ A 34-year-old woman with no known underlying lung disease 12-day history of cough. She initially had nasal

congestion and a mild sore throat, but now her symptoms are all related to a productive cough without paroxysms.

She denies any sick contacts. On physical examination she is not in respiratory distress and is afebrile with normal

vital signs. No signs of URI are noted. Scattered wheezes are present diffusely on lung auscultation.

34 y/o f, 12 day cough, initial

nasal congestion and sore

throat, cough, no fever

Acute bronchitis5 Mrs. L is a 61 year-old woman who presents with 4 days of a cough productive of yellow sputum. Her symptoms

started 4 days ago with rhinorrhea and productive cough. She initially had fevers as high as 101 for 2 days, but those

have now resolved. In the office, she has normal vital signs and a normal physical examination. She is otherwise

healthy except for high cholesterol for which she is being treated with atorvastatin. She has no drug allergies.

61 y/o f, 4 day cough, yellow

sputum, rhinorrhea, fever

(resolved)

Acute conjunctivitis¹ A 14-year-old boy with no significant past medical history presents 3 days after developing a red, irritated right eye

that spread to the left eye today. He has watery discharge from both eyes and they are stuck shut in the morning. He

reports recent upper respiratory symptoms and that several children at his day camp recently had pink eye. He

denies significant pain or light sensitivity and does not wear contact lenses. On examination, his pupils are equal and

reactive and he has a right-sided, tender preauricular lymph node. Penlight examination does not reveal any corneal

opacity.

14 y/o m, 3 days red, irritated

eye (spread from right to

left), discharge, URI

symptoms, no pain or light

sensitivity

Acute pharyngitis5 Mr. E is a 26 year-old man who presents to your office for complaints of sore throat, headache, and non-productive

cough. His symptoms started 2 days ago with acute onset of sore throat. He has been afebrile. His physical

examination is normal, except for some pharyngeal erythema. He is otherwise in good health, and is on no

medications except for acetaminophen for his sore throat and fever. He has no drug allergies.

26 y/o m, 2 day sore throat,

headache, cough, no fever

Self-care appropriate (n=15)

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Allergic rhinitis¹ A 22-year-old student presents with a 5-year history of worsening nasal congestion, sneezing, and nasal itching.

Symptoms are year-round but worse during the spring season. On further questioning it is revealed that he has

significant eye itching, redness, and tearing as well as palate and throat itching during the spring season. He

remembers that his mother told him at some point that he used to have eczema in infancy.

22 y/o m, 5 year Hx of nasal

congestion, sneezing, nasal

itching worse during spring

season, eye itching, redness,

tearing, palate and throat

itching, Hx of eczema in

infancy

Back pain¹ A 38-year-old man with no significant history of back pain developed acute LBP when lifting boxes 2 weeks ago. The

pain is aching in nature, located in the left lumbar area, and associated with spasms. He describes previous similar

episodes several years ago, which resolved without seeing a doctor. He denies any leg pain or weakness. He also

denies fevers, chills, weight loss, and recent infections. Over-the-counter ibuprofen has helped somewhat, but he

has taken it only twice a day for the past 3 days because he does not want to become dependent on painkillers. On

examination, there is decreased lumbar flexion and extension secondary to pain, but a neurologic exam is

unremarkable.

38 y/o m, acute low back pain

after lifting, no leg pain or

weakness, no fevers, chills,

weight loss, or recent

infections

Bee sting without

anaphylaxis¹

A 9-year-old boy is brought to the ER after being stung by a bee at a picnic. He is crying hysterically. After 15 minutes

of calming him down, exam reveals a swollen tender upper lip but no tongue swelling, no drooling, no stridor, no

rash, and no other complaints.

9 y/o m, bee sting, swollen

and tender upper lip; no

tongue swelling, drooling,

stridor, rash, or other

complaints

Canker sore¹ A 17-year-old male student presents with recurrent mouth ulceration since his early schooldays. He has no

respiratory, anogenital, gastrointestinal, eye, or skin lesions. His mother had a similar history as a teenager. The

social history includes no tobacco use and virtually no alcohol consumption. He has no history of recent drug or

medication ingestion. Extraoral exam reveals no significant abnormalities and specifically no pyrexia; no cervical

lymph node enlargement; nor cranial nerve, salivary, or temporomandibular joint abnormalities. Oral exam reveals a

well-restored dentition and there is no clinical evidence of periodontal-attachment loss or pocketing. He has five 4

mm round ulcers with inflammatory haloes in his buccal mucosae.

17 y/o m with recurrent

mouth ulceration for year, no

respiratory, anogenital,

gastrointestinal, eye, or skin

lesions, mother has similar

Hx, no Hx of recent drugs or

medication

Candidal yeast

infection6

Consider a 40-year-old, monogamous, married woman who calls to report a 2-day history of vaginal itching and

thick white discharge. She has no abdominal pain or fever. (in study 50% recommended physician visit)

40 y/o f, 2 day vaginal itching,

thick white discharge, no

abdominal pain or fever

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Constipation¹ A 5-month-old baby boy presents with difficulty and delay in passing hard stools. His mother reports that he strains

for several hours and may even miss a day, before passing stool with screaming and occasional spots of fresh blood

on the stool or diaper. He has recently been weaned from breastfeeding to cows' milk formula, which he had been

reluctant to drink initially. The child is thriving and now feeding normally. There was no neonatal delay in defecation

and no history of excessive vomiting or abdominal distension.

5 mo m, difficulty/delay in

passing hard stools, strains

for hours, may miss a day,

screams when passes stool

and occasional spots of

blood, weaned from

breastmilk to cows' milk, now

feeding normally

Eczema¹ A 12-year-old female presents with dry, itchy skin that involves the flexures in front of her elbows, behind her knees,

and in front of her ankles. Her cheeks also have patches of dry, scaly skin. She has symptoms of hay fever and has

recently been diagnosed with egg and milk allergy. She has a brother with asthma and an uncle and several cousins

who have been diagnosed with eczema.

12 y/o f, dry, itchy skin in

front of elbows, behind

knees, in front of ankles,

cheeks have patches of dry,

scaly skin, symptoms of hay

fever, egg and milk allergy,

brother has asthma and uncle

and cousins have eczema

Stye¹ A 30-year-old man presents with a painful, swollen right eye for the past day. He reports minor pain on palpation of

the eyelid and denies any history of trauma, crusting, or change in vision. He has no history of allergies or any eye

conditions and denies the use of any new soaps, lotions, or creams. On exam, he has localized tenderness to

palpation and erythema on the midline of the lower eyelid near the lid margin. The remainder of the physical exam,

including the globe, is normal.

30 y/o m, painful, swollen

right eye for past day, no Hx

of trauma, crusting, change in

vision, allergies, or eye

conditions, localized

tenderness, erythema

(redness)

Viral upper respiratory illnessMr. R. is a 56 year-old man who presents to you with 6 days of non-productive cough, nasal congestion, and green

nasal discharge. He has had intermittent fevers as high as 100.8. His physical examination is normal except for

rhinorrhea. He is otherwise healthy, except for chronic osteoarthritis of the right knee. He has no drug allergies.

56 y/o m, 6 day cough, nasal

congestion, green nasal

discharge, fever (100.8),

rhinorrhea

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Viral upper respiratory illness¹A 30-year-old man presents with a 2-day history of runny nose and sore throat. He feels hot and sweaty, has a mild

headache, is coughing up clear sputum and complains of muscle aches. He would like antibiotics as he was

prescribed them last year when he had a similar condition. On examination, he is afebrile, has a normal pulse, a

slightly inflamed pharynx and nontender cervical lymphadenopathy. There is no neck stiffness and his chest is clear.

He has tried over-the-counter cough medications, but has not found these helpful. He smokes 10 cigarettes per day.

30 y/o m, 2 day HX of runny

nose, sore throat, hot,

sweaty, mild headache, cough

with clear sputum, muscle

aches, no fever or neck

stiffness

Vomiting7 Elizabeth’s 2-year-old son has a fever and vomited twice. Elizabeth worries about dehydration, so she gives Jack a

sippy cup of apple juice. He immediately vomits up the juice. Elizabeth debates what to do next. Should she try to

reach Jack’s pediatrician or should she take Jack to the ED? Instead, she calls her triage nurse line. Temperature =

100.5

2 y/o m, low grade fever (T =

100.5), vomited twice, vomits

up juice

Table References

1. Epocrates. https://online.epocrates.com/noFrame/.

2. Lue J. NYU Medical Grand Rounds Clinical Vignette. 2012;

http://www.medicine.med.nyu.edu/education/im-residency-homepage/research-

opportunities/clinical-vignettes. Accessed September 8, 2014.

3. Halm EA, Teirstein AS. Clinical practice. Management of community-acquired pneumonia. N Engl J

Med. Dec 19 2002;347(25):2039-2045.

4. Plantz SH, Adler JN, eds. NMS Emergency Medicine. Baltimore: Williams & Wilkins; 1998. National

Medical Series for Independent Study.

5. Gidengil CA, Linder J, Beach S, Setodjian C, Hunter G, Mehrotra A. Using clinical vignettes to predict

antibiotic prescribing for acute respiratory infections. In review.

6. Sirovich BE, Gottlieb DJ, Welch HG, Fisher ES. Variation in the tendency of primary care physicians

to intervene. Arch Intern Med. Oct 24 2005;165(19):2252-2256.

7. Boroughs DS, Dougherty JA, Goldsmith C. Telephone Triage: Help Is Just a Call Away.

http://ce.nurse.com/RVignette.aspx?TopicId=718. Accessed September 10, 2014.

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OverallRequires

emergent care

Requires non-

emergent care

Self-care

appropriateOverall

Requires

emergent care

Requires non-

emergent care

Self-care

appropriateOverall

Requires

emergent care

Requires non-

emergent care

Self-care

appropriate

AskMD 43 29 47 55 75 64 80 82 - b

- b

- b

- b

Drugs.com 40 29 40 54 58 50 60 70 60 57 60 62

EarlyDoc 32 0 17 83 37 0 17 1 53 67 60 33

Esagil 20 7 27 27 50 57 40 53 b0

b b b

Family Doctor 47 40 50 50 56 40 50 50 54 50 50 60

FreeMD 36 33 33 43 48 40 53 50 59 67 87 21

HMS Family Health Guide 34 36 31 38 55 50 54 62 78 92 79 62

Healthline 38 33 31 39 58 40 60 73 - b

- b

- b

- b

Healthwise - a

- a

- a

- a

- a

- a

- a

- a 43 100 7 21

Healthy Children - a

- a

- a

- a

- a

- a

- a

- a 73 100 100 43

Isabel 44 33 73 27 84 80 87 87 51 100 53 0

iTriage 36 14 47 47 77 76 87 67 33 100 0 0

Mayo Clinic 17 7 21 23 76 57 86 85 - b

- b

- b

- b

MEDoctor 5 8 67 8 43 31 67 33 - b

- b

- b

- b

NHS - a

- a

- a

- a

- a

- a

- a

- a 52 87 20 50

Symcat 40 27 60 33 76 60 73 93 44 53 80 0

Symptify 29 7 20 60 44 33 40 60 70 92 71 50

Symptomate 31 50 30 10 34 58 30 10 64 78 67 0

SymptomMD - a

- a

- a

- a

- a

- a

- a

- a 71 86 71 57

WebMD 36 27 40 40 62 60 53 73 - b

- b

- b

- b

Correct Principle Diagnosis (%) Correct Diagnosis listed (%) Appropriate Triage (%)

Supplemental Table 2: Accuracy of diagnosis decision and triage advice for each symptom checker, stratified by severity of the SP vignette

a Symptom checker does not provide diagnosis suggestions b Symptom checker does not provide triage advice

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nly

Appropriate triage

% (95% CI)

All symptom checkers 56% (52-61)

Without iTriage 59% (54-63)

Without Symcat, Symptomate, and Isabel 58% (53-63)

Without Symcat, Symptomate, Isabel, and iTriage 61% (56-66)

Supplemental Table 3: Sensitivity analysis for appropriateness of triage

advice when symptom checkers that always provide advice to go to the

emergency department are removed (iTriage) and when symptom

checkers that never suggest self-care are removed (Symcat,

Symptomate, and Isabel).

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Documents

The Effectiveness of Symptom Checkers for Self-Diagnosis ... · Confidential: For Review Only 1 The Effectiveness of Symptom Checkers for Self-Diagnosis and Triage: Beyond “Googling”