Increasing the predictive value of clinic-based rapid HIV antibody screening using oral fluid and whole blood testing in 10 NYC STD clinics, New York City, 2006-2007

Julia R. Cummiskey, MPH1

Maushumi Mavinkurve, MPH1, Rachel Paneth-Pollak, MPH1, Jessica Borrelli, MPH1, Alexis V. Kowalski, MPH1, Susan Blank, MD MPH1,2

1New York City Department of Health & Mental Hygiene2Centers for Disease Control & Prevention

NYC STD Clinics

The Bureau of STD Control operates 10 clinics across the five boroughs of New York City

Services are free and confidential

NYC STD Clinics

Services include: Testing and treatment for Syphilis,

Gonorrhea, and Chlamydia HIV counseling and testing Hepatitis screening and vaccination PAP smears Emergency contraception

Rapid Testing, NYC STD Clinics

Jan. ’04 – Introduced rapid testing via finger-stick (FS)

Mar. ’05 – Replaced FS w/oral fluid (OF) rapid testing

Nov. ’05 – Documented cluster of false pos. OF tests

Dec. ’05 – Introduced FS as back-up for OF+*

* OF+ : preliminary positive OF results throughout

Consequences of False Positive Cluster, Nov./Dec. 2005

Patients: undue emotional stressStaff: loss of time and resources to locate

and notify non-casesPatients & staff: loss of confidence in

testing services

Response to Cluster of False Positives, NYC, Dec. 2005

Revised testing algorithm to include FS rapid test for OF+ samples (same assay)

Revised patient management algorithm accordingly

Whole-Blood (finger-stick)

Whole-Blood (finger-stick)+

Rapid Oral Fluid HIV Antibody

Test

Oral-Fluid + Oral-Fluid -

Finger-Stick Rapid HIV Test

Finger-Stick + Finger-Stick -

Confirmatory Testing (EIA / WB)

orConventional

(EIA / WB)

HIV Testing Algorithm, NYC STD Clinics, Dec. 2005

Rapid HIV Testing, NYC STD Clinics (2006)

53,169 OF rapid HIV antibody tests

497 (0.9%) OF+

Evaluation of Revised HIV Rapid Testing Algorithm

Objective:

Evaluate predictive value of using FS results to guide patient management

Evaluation of Revised HIV Rapid Testing Algorithm

Methods:

Compared results of FS rapid tests and Western Blot (WB) tests for patients with OF+ test results

OF Rapid HIV Testing, NYC STD Clinics, December 2005 – September 2007

97,653 OF rapid tests performed. 1,171 (1.2%) were OF+

815 (67%) followed by FS rapid HIV test

FS Rapid HIV Testing, NYC STD Clinics, December 2005 – September 2007

815 FS tests performed 678 (83.2%) + 137 (16.8%) -

All OF+ samples subjected to WB irrespective of FS results

Results of WB Tests, NYC STD Clinics, December 2005 – September 2007

678 Finger-Stick + 654 (98.1%) WB+ 13 (1.9%) WB –

Results of WB Tests, NYC STD Clinics, December 2005 – September 2007

137 Finger-Stick – 128 (99.2%) WB – 1 (0.8%) WB +

Positive Predictive Values

PPV of OF test alone 920/(920+146) = 86.3%

PPV of Finger-Stick following OF+ 654/(654+13) = 98.1%

Confirmatory WB Results for OF+ Tests With and Without FS Tests

795 OF+ tests, w/ FS 655 (82.4%) WB+

271 OF+ tests w/out FS 265 (97.8%) WB+

HIV Testing Algorithm in Practice, December 2005 – September 2007

OF +1171

NO FS DONE275 (25%)

FS DONE815 (74%)

FS +678 (83%)

FS -137 (17%)

WB +654 (99%)

WB -6 (1%)

WB +1 (<1%)

WB -127 (99%)

WB +265 (98%)

WB -6 (2%)

OF = Oral Fluid

FS = Finger-Stick

WB = Western Blot

Comparing FS Done & FS Not Done by Clinic December 2005 – September 2007

Characteristic Yes No P-value Clinic Central Harlem 57 6.9% 5 1.8% 0.002 Riverside 63 7.7% 26 9.5% 0.349 Corona 26 3.2% 31 11.3% <.0001 Fort Greene 133 16.2% 24 8.7% 0.002 Jamaica 80 9.7% 30 10.9% 0.578 Chelsea 136 16.6% 132 48.0% <.0001 East Harlem 82 10.0% 17 6.2% 0.057 Bushwick 60 7.3% 3 1.1% 0.0001 Staten Island 17 2.1% 1 0.4% 0.054 Morrisania 167 20.3% 6 2.2% <.0001

Total 821 275

Comparing FS Done & FS Not Done by Gender and BehaviorDecember 2005 – September 2007

Characteristic Yes No P-value Gender Male 629 76.6% 232 84.4% 0.007 (Male v. Female MSM 354 153 MSW 234 61 0.003 (MSM v. MSW) Female 191 23.3% 43 15.6%

Total 821 275

Comparing FS Done & FS Not Done by Testing History

December 2005 – September 2007

FS done? Characteristic Yes No P-value Previously Tested for HIV? (as reported by patient)

Yes 598 72.8% 221 80.4% 0.013 No 223 27.2% 54 19.6% 821 275

Previous HIV Test Result (as reported by patient)

Positive 29 3.5% 29 10.5% <.0001 Negative 787 95.9% 245 89.1% Unknown/Invalid 5 0.6% 1 0.4% 821 275

Lessons Learned

Intro. of less invasive rapid HIV testing correlates with increased demand for testing.

FS rapid HIV testing has applications for rapid OF HIV test quality assurance.

Lessons Learned

Patient mgmt. can be guided by combined outcomes of 2 rapid tests.

Significant differences appear between the individuals that got a 2nd rapid test and those who did not.

Post-Script

Late 2007, revised algorithm permitted rapid detection of another cluster of OF false positives.

We investigated and removed affected test lots from our clinics.

We notified other recipients of agency-purchased test kits.

Acknowledgments

Julia A. Schillinger, M.D., MSc. Preeti Pathela, DrPH Ellen J. Klingler, MPH Bernard M. Branson, M.D. Thomas A. Peterman, M.D., MSc. Special thanks to Jessica Borrelli,

MPH!