1. Can a second rapid HIV test discriminate false positives as effectively as a Western Blot? The NJ Experience Evan M. Cadoff, MD Robert Wood Johnson Medical School New Brunswick, NJ Cadoff EM, Cadoff RA, Salaru G, Paul SM, Martin EG

2. NJHIV Rapid Testing Program Under direction of RWJMS OraQuick started November 1, 2003 Oversees about 2/3 of NJ CTS HIV testing Confirmatory testing at PHEL in Trenton NJHIV oversees followup of all discordant NJHIV does not evaluate linkage to care

3. Preliminary Positive Followup 7.1% refused blood draw for confirmation 25.8% of those drawn did not return for results 70.1% of confirmed positives got their results and post-test counseling Rapid confirmation could improve effectiveness of prevention and referral/entry to care and treatment services

4. Data Needs for Proposed Testing Strategies 1.Are there false negative screening tests? 2.Can true positive screening tests be confirmed by a second rapid test, rather than WB/IFA/NAT? 3.Can false positive screening tests (ie discordants) be detected by a second rapid test, rather than waiting for WB/IFA/NAT? 4.Impact on linkage to care? 5.How well can inconclusive “second-round” test results (eg, WB vs a second rapid test) be resolved?

5. Two NJHIV Datasets Confirm true positives Evaluate confirmed false positives Resolve discordants and indeterminate confirmatory test results

6. Nov 2003 – April 2005 data Rapid testing by blood only using OraQuick Western Blot specimens sent to PHEL All avialable WB specimens evaluated by: Repeat OraQuick on blood Trinity Uni-Gold MedMira Reveal BioRad Multispot Followup of clients with discordant results

7. Nov 2003 – April 2005 data 15,923 OraQuick tests statewide 363 preliminary postive samples to state lab for Western Blot 355 Western Blot positive confirmed by other rapids 8 Western Blot negative discordants all repeat OraQuick positive one reactive Multispot by one reader others all negative 6 preliminary positive is false positive 25% with no clinical followup 15,923 355 8 Strategy 1, Data Need 3

8. Discordant followup Four visits: 1.Rapid test. If prelim pos, draw blood and send to Trenton for Western Blot. 2.Return in a week, and get discordant confirmatory test result. 3.Return at a month to have more blood drawn (repeat antibody; and NAAT). 4.Come back a week later for definitive result.

9. Discordant followup

10. Revised discordant followup Three Visits 1.If rapid test is reactive, draw Western Blot. 2.Return in a week. Get discordant confirmatory test result and draw NAAT. 3.Third visit for NAAT result. or Two Visits 1.If rapid test is reactive, draw both Western Blot and NAAT. 2.NAAT is run if WB is discordant, and both results are available at second visit.

11. Revised discordant followup Three Visits 1.If rapid test is reactive, draw Western Blot. 2.Return in a week. Get discordant confirmatory test result and draw NAAT. 3.Third visit for NAAT result. or Two Visits 1.If rapid test is reactive, draw both Western Blot and NAAT. 2.NAAT is run if WB is discordant, and both results are available at second visit. or One visit with rapid confirmation would be better!

12. Jan 2006 – Oct 2007 data Retained specimens from followup testing for discordant Western Blot results. Cannot confirm true positives. Can evaluate discordants and indeterminates (if they had followup).

13. Jan 2006 – Oct 2007 data Samples are not from the same time as screening OraQuick. Used CLIA-waived tests: Repeat OraQuick on blood Trinity Uni-Gold Clearview StatPak

14. Jan 2006 – Oct 2007 data 108 false positive; 72 without followup may be false positive [Strategy 1, Data need 3; Strategy 4, Data need 5a] No false positive strategy results [Strategy 4,Data need 1]; No false negative A2 or A3 [Strategy 4, Data need 4, 5b]

15. Jan 2006 – Oct 2007 data No false positive strategy results [Strategy 3, Data need 1] 1 false positive A1-blood result [Strategy 3, Data need 4a,5] 91 false positive A1-oral results [Strategy 3, Data need 5] No false negative A2 results [Strategy 3, Data need 4b]

16. Jan 2006 – Oct 2007 data No false positive strategy results [Strategy 2, Data need 1] 17 Inconclusive results with false positive A1 [Strategy 2, Data need 4]

17. Data Needs for Proposed Testing Strategies All followups on negative Western Blot were NAAT negative (OraQuick false positive). All were "second rapid" negative. Oral OraQuick followed by blood OraQuick: 3 tested at CTS site on False Positives: 2 blood negative; 1 blood positive 56 tested on followup blood specimen all blood negative OraQuick blood discordant 11 tested on followup blood specimen 7 negative 4 repeat positive

18. Observations Indeterminate Western Blot: 12 total: 4 no followup; 3 QNS 3 NAAT negative were "second rapid" negative 2 NAAT positive were "second rapid" positive

19. Rapid Confirmation Is Needed Rapid confirmation of preliminary positive results is necessary: 30-40% without followup would have benefited from rapid confirmatory testing.

20. Rapid Confirmation Works All 355 true positives confirmed using a second rapid test (from a pool of about 16,000 clients tested) All 65 false positives with followup available were negative using a second rapid test (from a pool of about 120,000 clients tested) Indeterminate Western Blots were resolved by a second rapid

21. Conclusions Rapid confirmation of preliminary positive results is necessary. Rapid confirmation of preliminary positive results works at least as well as Western Blot testing.