UK Standards for Microbiology Investigations

8/13/2019 UK Standards for Microbiology Investigations

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Issued by the Standards Unit, Microbiology Services Division, HPA

Virology | V 4 | Issue no: 5.2 | Issue date: 28.06.12 | Page: 1 of 18

UK Standards for Microbiology Investigations

Hepatitis B Diagnostic Serology in the Immunocompetent (includingHepatitis B in Pregnancy)

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Hepatitis B Diagnostic Serology in the Immunocompetent (including Hepatitis B in Pregnancy)


UK Standards for Microbiology Investigations | Issued by the Standards Unit, Health Protection Agency

AcknowledgmentsUK Standards for Microbiology Investigations (SMIs) are developed under the auspices of theHealth Protection Agency (HPA) working in partnership with the National Health Service (NHS),

Public Health Wales and with the professional organisations whose logos are displayed belowand listed on the websitehttp://www.hpa.org.uk/SMI/Partnerships.SMIs are developed,reviewed and revised by various working groups which are overseen by a steering committee(seehttp://www.hpa.org.uk/SMI/WorkingGroups).

The contributions of many individuals in clinical, specialist and reference laboratories who haveprovided information and comments during the development of this document areacknowledged. We are grateful to the Medical Editors for editing the medical content.

For further information please contact us at:

Standards UnitMicrobiology Services Division

Health Protection Agency61 Colindale AvenueLondon NW9 5EQ

E-mail:[email protected]

Website:http://www.hpa.org.uk/SMI

The UK Standards for Microbiology Investigations are produced in association with:

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UK Standards for Microbiology Investigations: StatusUsers of SMIsThree groups of users have been identified for whom SMIs are especially relevant:

SMIs are primarily intended as a general resource for practising professionals in the fieldoperating in the field of laboratory medicine in the UK. Specialist advice should beobtained where necessary.

SMIs provide clinicians with information about the standard of laboratory services theyshould expect for the investigation of infection in their patients and the documentsprovide information that aids the electronic ordering of appropriate tests from hospitalwards.

SMIs also provide commissioners of healthcare services with the standard ofmicrobiology investigations they should be seeking as part of the clinical and public

health care package for their population.

Background to SMIsSMIs comprise a collection of recommended algorithms and procedures covering all stages ofthe investigative process in microbiology from the pre-analytical (clinical syndrome) stage tothe analytical (laboratory testing) and post analytical (result interpretation and reporting)stages.

Syndromic algorithms are supported by more detailed documents containing advice on theinvestigation of specific diseases and infections. Guidance notes cover the clinical background,differential diagnosis, and appropriate investigation of particular clinical conditions. Qualityguidance notes describe essential laboratory methodologies which underpin quality, forexample assay validation, quality assurance, and understanding uncertainty of measurement.

Standardisation of the diagnostic process through the application of SMIs helps to assure theequivalence of investigation strategies in different laboratories across the UK and is essentialfor public health interventions, surveillance, and research and development activities. SMIsalign advice on testing strategies with the UK diagnostic and public health agendas.

Involvement of Professional OrganisationsThe development of SMIs is undertaken within the HPA in partnership with the NHS, PublicHealth Wales and with professional organisations.

The list of participating organisations may be found athttp://www.hpa.org.uk/SMI/Partnerships.Inclusion of an organisations logo in an SMI impliessupport for the objectives and process of preparing SMIs. Representatives of professionalorganisations are members of the steering committee and working groups which developSMIs, although the views of participants are not necessarily those of the entire organisationthey represent.

#UK Standards for Microbiology Investigations were formerly known as National Standard Methods.

Microbiology is used as a generic term to include the two GMC-recognised specialties of Medical Microbiology (which includes Bacteriology,Mycology and Parasitology) and Medical Virology.

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SMIs are developed, reviewed and updated through a wide consultation process. The resultingdocuments reflect the majority view of contributors. SMIs are freely available to view athttp://www.hpa.org.uk/SMIas controlled documents in Adobe PDF format.

Quality AssuranceThe process for the development of SMIs is certified to ISO 9001:2008.

SMIs represent a good standard of practice to which all clinical and public health microbiologylaboratories in the UK are expected to work. SMIs are well referenced and represent neitherminimum standards of practice nor the highest level of complex laboratory investigationpossible. In using SMIs, laboratories should take account of local requirements and undertakeadditional investigations where appropriate. SMIs help laboratories to meet accreditationrequirements by promoting high quality practices which are auditable. SMIs also provide areference point for method development. SMIs should be used in conjunction with other SMIs.

UK microbiology laboratories that do not use SMIs should be able to demonstrate at leastequivalence in their testing methodologies.

The performance of SMIs depends on well trained staff and the quality of reagents andequipment used. Laboratories should ensure that all commercial and in-house tests have beenvalidated and shown to be fit for purpose. Laboratories should participate in external qualityassessment schemes and undertake relevant internal quality control procedures.

Whilst every care has been taken in the preparation of SMIs, the HPA, its successororganisation(s) and any supporting organisation, shall, to the greatest extent possible underany applicable law, exclude liability for all losses, costs, claims, damages or expenses arising outof or connected with the use of an SMI or any information contained therein. If alterations aremade to an SMI, it must be made clear where and by whom such changes have been made.

SMIs are the copyright of the HPA which should be acknowledged where appropriate.

Microbial taxonomy is up to date at the time of full review.

Equality and Information GovernanceAn Equality Impact Assessment on SMIs is available athttp://www.hpa.org.uk/SMI.

The HPA is a Caldicott compliant organisation. It seeks to take every possible precaution toprevent unauthorised disclosure of patient details and to ensure that patient-related recordsare kept under secure conditions.

Suggested citation for this document:Health Protection Agency. (2012). Hepatitis B Diagnostic Serology in the Immunocompetent(including Hepatitis B in Pregnancy) UK Standards for Microbiology Investigations. V 4 Issue 5.2.http://www.hpa.org.uk/SMI/pdf.

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ContentsACKNOWLEDGMENTS ............................................................................................................ 2UK STANDARDS FOR MICROBIOLOGY INVESTIGATIONS: STATUS ............ ............ ......... ............ ..... 3AMENDMENT TABLE ............................................................................................................... 6HEPATITIS B SURFACE ANTIGEN HBSAG) CONFIRMATION BY NEUTRALISATION FLOWCHART .......... 7HEPATITIS B VIRUS SEROLOGY HBSAG CONFIRMATION BY ALTERNATIVE ASSAY FLOWCHART ....... 9HEPATITIS B SURFACE ANTIGEN CONFIRMED REACTIVES FLOWCHART ........................................ 11HEPATITIS B REPORTING FOR IMMUNOCOMPETENT INDIVIDUALS .............................................. 13NOTIFICATION TO THE HPA ................................................................................................... 17REFERENCES ........................................................................................................................ 18

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Amendment TableEach SMI method has an individual record of amendments. The current amendments are listedon this page. The amendment history is available [email protected].

New or revised documents should be controlled within the laboratory in accordance with thelocal quality management system.

Amendment No/Date. 8/28.06.12

Issue no. discarded. 5.1

Insert Issue no. 5.2

Section s) involved. Amendment.Whole document. Minor formatting amendments.

Amendment No/Date. 7/02.11.11

Issue no. discarded. 5

Insert Issue no. 5.1

Section s) involved. Amendment.Whole document. Document presented in a new format.

Appendix Removed.

References. Some references updated.

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mailto:[email protected]:[email protected]:[email protected]:[email protected]


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Hepatitis B Surface Antigen HBsAg) Confirmation byNeutralisation FlowchartHBsAg assay

a

HBsAg minimum target sensitivity level of 0.05 iu / mL

Negative Reactive

Confirm specificity by

neutralisation

REPORT:

HBsAg not detected

Repeat from the original

sample

Not confirmed Confirmed

REPORT:

HBsAg detected

Confirmed by neutralisation. Please send a

further sample for confirmationc

REPORT:

HBsAg not detectedb

Reactive Negative

REPORT:

HBsAg

not detected

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Footnotesa) It is recommended that only those assays which are able to detect immune / vaccine

escape variants should be used.

b) Haemolysed samples (eg cadaver samples) are prone to give non-neutralisable falsereactive results.

c) All newly diagnosed patients with chronic hepatitis should be referred to ahepatologist.

Please see Appendix for key to Visio flow chart symbols.

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Hepatitis B Virus Serology HBsAg Confirmation byAlternative Assay FlowchartHBsAg assay

HBsAg minimum target sensitivity level of 0.05 iu/mL

Confirmatory HBsAg test from original sample

using alternative assay of at least equivalent

sensitivity

REPORT:

Hepatitis B surface antigen not detected

Negative Reactivea,b

Repeat 1stassay from original

sample

(if available)c

See HBsAg Confirmed

Reactive algorithm

Both tests negative1

sttest reactive

a

2nd

test negative

REPORT:

Hepatitis B surface antigen not detectedAnti-HBc test

Anti-HBc negative Anti-HBc reactivea

REPORT:

HBsAg equivocal,

Anti-HBc negative. Likely to be non specific

surface antigen reactivity. Request another

sample.

Testing for other markers as appropriate see

table

Reactivea

Negative

REPORT:

HBsAg equivocal, Anti-HBc reactive.

Further test results to follow.

Please send another sample

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Footnotesa) It is recommended that only those assays which are able to detect immune / vaccine

escape variants should be used.

b) Haemolysed samples (eg cadaver samples) are prone to give non-neutralisable falsereactive results.

c) All newly diagnosed patients with chronic hepatitis should be referred to ahepatologist.

d) Please see Appendix for key to Visio flow chart symbols.

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Hepatitis B Surface Antigen Confirmed Reactives FlowchartAnti-HBc total

Positivea,b Negative

Core IgM

Negative

HBV DNAc

Positive Negative

Perform HBeAg / Anti HBed

For interpretation: see Table For interpretation: see Table

Positive(50 PEIU/mL)

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Footnotesa) All newly diagnosed patients with chronic hepatitis should be referred to a hepatologist.b) When interpreting anti-HBc reactivity consider the possibility of false reactivity if weak.c) Testing a further sample or doing other Hepatitis B markers may give a useful final status

before the HBV DNA result is available.

d) Hepatitis D (delta) virus testing should be considered at presentation of chronic HBVinfection and during any clinical flares or during acute infection, especially if complicated byacute liver failure.

Please see Appendix for key to Visio flow chart symbols.

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Hepatitis B reporting for immunocompetent individuals*HBs Ag Anti HBc

(total)HBc IgM HBe Ag

d Anti HBe

eAnti HBs Hep B

DNAf

Suggested wording of report comment

(see footnotes for further information and actions)

1 Negative Negative Negative/

Not tested

No evidence of current or past hepatitis B infection (see note ii).

2 Negative Positive Positive Consistent with past hepatitis B infection**.

3a, b

Negative Positive Negative Consistent with probable past hepatitis B infection** (consider the possibilityof false anti-HBc).

4 Negative Negative Positive No evidence of current or past infection with hepatitis B.

Anti HBs is compatible with a vaccine response.

5b Negative Positive Positive

(any level)

Negative Negativeor Positive

Negativeor LowPositive

Suggests relatively recent resolving infection with hepatitis B. Is there a historyof infection or recent jaundice? Please send a repeat sample to confirm.

6c Positive Negative Negative Negative Negative Negative Positive Indicates early acute infection with hepatitis B. Please repeat testing in amonths timevii.

7 Positive Negative Negative Negative HBsAg detected. No evidence of viral replicationg. Has this patient beenrecently immunised? The HBsAg in vaccine can be detectable for about oneweek after vaccination1.

8 Positive Negative Negative Positive Negative Negative Positive Indicates early acute infection with hepatitis B. Please repeat immediately and

if confirmed test again in three monthsg.

9

Positive Positive Positive

> 50PEIU/mL

Positive Negative Negative Indicates recent infection with hepatitis Bg. Immediate repeat and send

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10 Positive Positive Positive


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Notes relating to the tableAcute infectious hepatitis is a notifiable disease. All HBsAg positive patients should be reportedpromptly: see Notification and Referral section.

The testing algorithm wording of reports assumes this is the first sample received from thispatient. Later samples will require modified report comments.

Anti-HBc IgM may be detectable in recent acute hepatitis B or during a flare of viral replicationand may be seen in chronic infection with hepatitis B. In determining whether a case is likelyto be acute hepatitis B the clinical details as well as any earlier results on record and the levelof anti-HBc IgM are useful. Acute cases are more likely to have levels over 200 Paul EhrlichUnits/mL. Levels between 50 and 200 are probably acute, levels below 50 are probably a flareof chronic infection, but may be due to late acute infection. Note: interpretative commentsshould be provided on reports: see CPA Standards for the Medical Laboratory (2007) StandardG5. Patients considered to be at an increased risk of HBV exposure or having chronic liverdisease should be tested for anti-HBc when found to be HBsAg negative.

Hepatitis B may reactivate in patients who are immunocompromised

a) It is advisable to confirm isolated anti-HBc positive results with a second assay, asisolated anti-HBc sometimes represents false reactivity.

b) In clinical scenario of recent acute liver failure (fulminant hepatitis) HBsAg may benegative due to the pronounced immune response and rapid viral clearance of HBV;total anti-HBc and anti-HBc IgM may then be the only positive serological markers.

c) The detection of HBsAg without evidence of anti-HBc and anti-HBc IgM is associatedwith early acute infection before antibody production. HBV DNA testing is essential toconfirm this. Request repeat sample to confirm identity of patient and to check forconfirmation of acute Hepatitis B virus infection by development of other markers,

these can take many weeks to evolve and may not be accompanied by symptoms ofacute hepatitis.

d) HBeAg positive samples are strongly associated with high infectivity unless HBVreplication is being suppressed by antiviral therapy.

e) Anti-HBe positive patients often have low infectivity, but a proportion have precoremutant virus infection with high HBV DNA levels.

f) HBV DNA PCR is widely available in virology specialist centres and can be used toevaluate the viral load. This has been shown to have prognostic value, independent ofHBe status in the evaluation risk of cirrhosis and development of hepatocellularcarcinoma in patients with chronic infection. It is also used to monitor antiviral therapy.

g) Please screen and immunise sexual household contact.In pregnant patients testing HBsAg positive, additional comments should be added to guideimmunisation and follow-up of the baby after birth. See below for further details.

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Hepatitis B in pregnancy The general testing strategies and reporting and notification patterns for hepatitis B

infected pregnant women are identical to those for other individuals.

Additional reporting to specialist midwives or similar healthcare workers responsible forthe care of pregnant women and their babies should be in place locally.

Vertical transmission of hepatitis B to the neonate is a substantial risk and prophylaxisfor the neonate should be arranged well before delivery wherever possible. Localarrangements may vary.

The guidance promulgated by the DH in Chapter 18 of Immunisation againstInfectious Diseaseshould be followed taking particular note of online Chapterupdates.

Reference should also be made to DH Guidance Screening for infectious diseases inpregnancy: Standards to support the UK antenatal screening programme.

All children born to mothers infected with HBV should be followed up to ensure completion ofimmunisation in accordance with national guidance. Testing for HBsAg at 1 year is currentlyrecommended.

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http://www.dh.gov.uk/en/Publichealth/Healthprotection/Immunisation/Greenbook/dh_4097254http://www.dh.gov.uk/en/Publichealth/Healthprotection/Immunisation/Greenbook/dh_4097254http://www.dh.gov.uk/en/Publichealth/Healthprotection/Immunisation/Greenbook/dh_4097254http://www.dh.gov.uk/en/Publichealth/Healthprotection/Immunisation/Greenbook/dh_4097254http://www.dh.gov.uk/en/Publicationsandstatistics/Publications/PublicationsPolicyAndGuidance/DH_4050934http://www.dh.gov.uk/en/Publicationsandstatistics/Publications/PublicationsPolicyAndGuidance/DH_4050934http://www.dh.gov.uk/en/Publicationsandstatistics/Publications/PublicationsPolicyAndGuidance/DH_4050934http://www.dh.gov.uk/en/Publicationsandstatistics/Publications/PublicationsPolicyAndGuidance/DH_4050934http://www.dh.gov.uk/en/Publicationsandstatistics/Publications/PublicationsPolicyAndGuidance/DH_4050934http://www.dh.gov.uk/en/Publicationsandstatistics/Publications/PublicationsPolicyAndGuidance/DH_4050934http://www.dh.gov.uk/en/Publichealth/Healthprotection/Immunisation/Greenbook/dh_4097254http://www.dh.gov.uk/en/Publichealth/Healthprotection/Immunisation/Greenbook/dh_4097254


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Notification to the HPA2,3The Health Protection (Notification) regulations 2010 require diagnostic laboratories to notifythe Health Protection Agency (HPA) when they identify the causative agents that are listed in

Schedule 2 of the Regulations. Notifications must be provided in writing, on paper orelectronically, within seven days. Urgent cases should be notified orally and as soon aspossible, recommended within 24 hours. These should be followed up by written notificationwithin seven days. For the purposes of the Notification Regulations, the recipient of laboratorynotifications is the local HPA office. If a case has already been notified by a registered medicalpractitioner, the diagnostic laboratory is still required to notify the case if they identify anyevidence of an infection caused by a notifiable causative agent.

Notification under the Health Protection (Notification) Regulations 2010 does not replacevoluntary reporting to the HPA. The vast majority of NHS laboratories voluntarily report a widerange of laboratory diagnoses of causative agents to the HPA and many HPA offices haveagreements with local laboratories for urgent reporting of some infections. This should

continue.(Note: The Health Protection Legislation Guidance (2010) includes reporting of HIV & STIs,HCAIs and CJD under Notification Duties of Registered Medical Practitioners: it is not notedunder Notification Duties of Diagnostic Laboratories).

Other arrangements exist in Scotland4and Wales5.

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UK Standards for Microbiology Investigations | Issued by the Standards Unit Health Protection Agency

References1. Dow BC, Yates P, Galea G, Munro H, Buchanan I, Ferguson K. Hepatitis B vaccinees may be mistaken for

confirmed hepatitis B surface antigen-positive blood donors. Vox Sang 2002;82:15-7.

2. Health Protection Agency. Laboratory Reporting to the Health Protection Agency: Guide for DiagnosticLaboratories. 2008.

3. Department of Health. Health Protection Legislation (England) Guidance 2010.http://www.dh.gov.uk/en/Publicationsandstatistics/Publications/PublicationsPolicyAndGuidance/DH_114510.p. 1-112.

4. Scottish Government. Public Health (Scotland) Act 2008.http://www.scotland.gov.uk/Topics/Health/NHS-Scotland/publicact/Implementation/Timetable3333/Part2Guidance/Q/EditMode/on/ForceUpdate/on.

5. The Welsh Assembly Government. Health Protection Legislation (Wales) Guidance 2010.http://wales.gov.uk/docs/phhs/publications/100716ahealthprotguidanceen.pdf.

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UK Standards for Microbiology Investigations