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Rapid HIV Testing and Its Role in Advancing HIV Prevention: 2004 Update Bernard M. Branson, M.D. Chief, Lab Determinants and Diagnostics Section Centers.

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Presentation on theme: "Rapid HIV Testing and Its Role in Advancing HIV Prevention: 2004 Update Bernard M. Branson, M.D. Chief, Lab Determinants and Diagnostics Section Centers."— Presentation transcript:

1 Rapid HIV Testing and Its Role in Advancing HIV Prevention: 2004 Update Bernard M. Branson, M.D. Chief, Lab Determinants and Diagnostics Section Centers for Disease Control and Prevention

2 Three FDA-approved Rapid HIV Tests Sensitivity (95% C.I.) Specificity (95% C.I.) OraQuick 99.6 (98.5 – 99.9) 100% (99.7 – 100) Reveal 99.8 (99.2 – 100) 99.1 (98.8 – 99.4) Uni-Gold Recombigen 100 (99.5 – 100) 99.7 (99.0 – 100)

3 Three FDA-approved Rapid HIV Tests Specimen type CLIA category OraQuick Fingerstick, whole blood, (oral fluid?) Waived Reveal Serum, plasmaModerate Complexity Uni-Gold Recombigen Serum, plasma, whole blood Moderate Complexity

4 OraQuick: Fingerstick, whole blood

5 Obtain finger stick specimen…

6 … or whole blood

7 Loop collects 5 microliters of whole blood

8 Insert loop into vial and stir

9 Insert device; test develops in 20 minutes

10 PositiveNegative Reactive Control Positive HIV-1 Read results in 20 – 40 minutes T T C C

11 Sold only to “clinical laboratories” To perform CLIA-waived tests, entities must: 1)Enroll in CLIA program 2)Obtain a Certificate of Waiver 3)Pay a biennial fee 4)Follow manufacturers’ instructions 5)Meet state requirements Requirements for OraQuick Testing

12 Have an adequate quality assurance program Assurance that operators will receive and use instructional materials QA guidelines for OraQuick testing and sample forms: Requirements for OraQuick Testing

13 Oral fluid specimens: Reduce hazards, facilitate testing in field settings

14 Reveal HIV-1 Rapid Antibody Test: Serum, Plasma

15 Centrifuge to obtain serum or plasma

16 Add 20 drops of buffer to reconstitute conjugate. (Refrigerate to store)

17 Add 3 drops buffer to moisten membrane

18 Add one drop of serum or plasma, followed by 3 drops of buffer.

19 Add 4 drops of conjugate solution

20 Add 3 drops of buffer to wash

21 Read results immediately Positive Negative

22 Uni-Gold Recombigen: Serum, plasma, whole blood

23 Add 1 drop specimen to well

24 Add 4 drops of wash solution

25 Read results in 10 minutes

26 Point-of-Care Testing To expand testing in non-clinical settings: –Fingerstick or oral fluid specimen –One-step –Easy to interpret –Internal control

27 The Need for Training Blood & body fluid precautions Obtaining the specimen (finger stick or blood draw) Performing the test Providing test results and counseling Quality assurance OSHA requirements

28 Remember the tradeoffs… Good News: More HIV-positive people receive their test results. Bad News: Some people will receive a false- positive result before confirmatory testing.

29 Reports from the 2003 HIV Prevention Conference Promising news with rapid HIV tests for – –Routine screening in medical settings –Increasing receipt of results at CT sites –Screening in labor and delivery –Outreach testing

30 Routine HIV Screening in Medical Care Settings Cook County Hospital ED, Chicago OraQuick testing since October 02  60% accept HIV testing  98% receive test results  2.8% new HIV positive  80% entered HIV care Now underway in Chicago, Boston, Los Angeles 4 new demonstration projects (Wisconsin, Massachusetts, Los Angeles, New York)

31 HIV Screening in Acute Care Settings Cook County ED, Chicago2.3% Grady ED, Atlanta2.7% Johns Hopkins ED, Baltimore3.2% HIV testing sites1.3% New HIV+

32 HIV Screening with OraQuick in Labor and Delivery: the MIRIAD Study Testing of pregnant women in labor for whom no HIV test results are available; 12 hospitals in 5 cities: Atlanta, Chicago, Miami, New Orleans, New York To date  4597 women screened  34 new HIV infections identified  2 false positive OraQuick tests, no false negatives  8 false-positive EIAs

33 Turnaround Times for Rapid Test Results, Point-of-Care vs Lab Testing Point-of-care testing: median 45 min – (range 30 min – 2.5 hours) Same test in Laboratory: median 3.5 hours – (range 94 min – 16 hours) MMWR 52:36, Sept 16, 2003

34 OraQuick Outreach to High-risk Persons of Color On-site testing at sites throughout the community Group pretest counseling. Individual testing and post-test counseling. Patrick Keenan MD University of Minnesota Medical School Department of Family Practice and Community Health

35 OraQuick Fingerstick Results: 7/02 – 6/03 N = 1021 Preliminary positive 5 (0.5%) True positives 4 (0.4%) False Positives 1 (0.1%) Sensitivity4/4 (100%) Specificity1016/1017 (99.9%) Positive Predictive Value4/5 (80%)

36 Results 99.7% of clients received their test results and post-test counseling. The average time between fingerstick and learning test result was 28 minutes.

37 Client Survey Results “I would rather have my finger stuck than have blood drawn from my vein” Agree or strongly agree = 95% Disagree or strongly disagree = 5%

38 Post-Marketing Surveillance 14 states in 2003, expansion in 2004 as more project areas implement rapid testing (Note: Supplement to Program Announcement) Monitoring:  Changes in utilization of testing  Acceptance (choice of tests)  Client and counselor satisfaction  Follow-up on false-positives  Adverse events

39 Initial Observations 95% of persons opt for the rapid HIV test; 34% of those tested say they would not have been tested if rapid test not available (New York) In one clinic for homeless persons, HIV prevalence among those tested rose from 4% to 12% after introduction of rapid tests (San Francisco) 30% of the number of HIV-positive persons identified in all of last year were identified in the first month rapid testing was introduced (Utah) 98% - 100% of those tested receive their test results

40 Post-Marketing Surveillance In New York State test sites: 30% increase in persons tested  85% increase in MSM  42% increase in IDU  96% increase in persons with hx of STD diagnosis Counselors’  confidence in their overall role in rapid testing rose from 54% to 100% after first 12 weeks of testing  scores on proficiency specimens at 12 weeks were 100%

41 Confirmatory Testing For Western blot:  Venipuncture for whole blood  Oral fluid specimen  Dried blood spots on filter paper Confirmatory test essential (not just EIA!)

42 Additional Resources General and technical information (updated frequently):

43

44 Interpreting Rapid Test Results For a laboratory test: Sensitivity : Probability test=positive if patient=positive Specificity : Probability test=negative if patient=negative Predictive value : Probability patient=positive if test=positive Probability patient=negative if test=negative

45 Example: Test 1,000 persons HIV prevalence = 10% True positive:False positive: Positive predictive value:100/104 = 96% 1004 Test Specificity = 99.6%(4/1000)

46 Example: Test 1,000 persons Test Specificity = 99.6% (4/1000) HIV prevalence = 10% True positive: 100False positive: 4 Positive predictive value: 100/104 = 96% HIV prevalence = 0.4% True positive:4False positive:4 Positive predictive value:4/8 = 50%

47 Positive Predictive Value of a Single Test Depends on Specificity & Varies with Prevalence Test Specificity HIV Prevalence Predictive Value, Positive Test 10% 99% 98% 92% 5% 98% 96% 85% 2% 95% 91% 69% 1% 91% 83% 53% 0.5% 83% 71%36% 0.3% 75%60% 25% 0.1% 50% 33% 10% OraQuic k EIAReveal 99.9%99.8%99.1%


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