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A Response to “Negative rapid HIV antibody testing during early HIV infection”
Submit responseDr. Stekler’s letter reported two cases where a health worker missed weak positive OraQuick rapid HIV finger-stick results and failed to identify people with early HIV infection. These cases were identified through repeat OraQuick (OraSure Technologies) testing of the frozen serum specimens, concurrent HIV Enzyme Immunoassay (EIA, 3rd generation [HIVAB HIV-1/HIV-2 (rDNA) EIA, Abbott]), Western Blot (Genetic Systems HIV-1 Western Blot, Bio-Rad), and pooled RNA testing. [1] One other missed infection was mentioned, but repeat testing with OraQuick was not done.
The Authors discuss that people with delayed gp41 production during acute infection may be missed by the OraQuick test. However, it is important to view these data in the context of other data evaluating the OraQuick assay in early HIV infection. A study of sero-conversion panels comparing OraQuick plasma tests with a 3rd generation EIA revealed that the OraQuick test became positive in several panels before the Western blot showed a gp41 band.[2] On average the 3rd generation EIA did pick up new infection 2.5 days before the OraQuick plasma test. The accuracy of the OraQuick assay on fresh oral fluid specimens, as compared to plasma, during sero-conversion is yet to be established.
The authors conclude that “widespread use of rapid HIV antibody tests could have deleterious public health effects if rapid tests are consistently less sensitive or more prone to operator error during early HIV infection.”
To determine the true impact of rapid HIV testing on public health, we must weigh several factors including the relative acceptability, effectiveness and cost of alternative testing strategies, and the relative impact of alternative counseling strategies on HIV prevention. Randomized controlled trials have demonstrated that rapid tests for HIV are more acceptable and more effective for providing knowledge of HIV status than standard EIA tests, [3] and are also less costly. [4] Given the demonstrated high sensitivity (100%) and specificity (99.6) of OraQuick, [5] it is likely that the benefits of OraQuick testing will outweigh the risks of missing rare sero-converters in most communities with relatively low incidence of acute infection.
In high incidence settings, the benefits of rapid oral fluid HIV testing may be off-set by sero-converters missed. In these settings, another parameter that may need to be taken into account is the data that suggests that in some high-risk populations, one dose of counseling with rapid testing is less effective than two doses of counseling with standard testing [6]. Although this would not be a relevant factor in many settings if the new CDC recommendations for testing without counseling are followed [7].
In order to make an evidence based decision about the use of rapid oral fluid testing in public health settings the following studies will be necessary: 1) A study determining the time-course of conversion for oral fluid rapid testing as compared to other testing strategies; and 2) A decision analysis that considers, for different testing and counseling strategies, the relative rates of testing acceptance, receipt of accurate results (in early and late infection), and counseling impact on HIV transmission. A sensitivity analysis based on varying incidence will determine the relative effectiveness of rapid vs. standard testing strategies in different communities, and will suggest when concurrent pooled RNA testing would be indicated.
This data is critically needed to inform the design of effective programs to reach the hundreds of thousands of people in the United States, and millions internationally, who are currently unaware of their HIV infection, unknowingly spreading HIV to others, and unable to take advantage of life prolonging treatments.
References
1. Stekler J, Swenson PD, Wood RW, Handsfield HH and Golden MR. Targeted screening for primary HIV infection through pooled HIV-RNA testing in men who have sex with men. AIDS 2005;19:1323-5.
2. Lee SR, Guillon G., Ferko, G. et al. (2006) Performance of a rapid Point of Care Test for HIV Antibodies. 21st Int’l Symposium: Refining Point of Care Strategies for Critical and Emergency Care.
3. Spielberg F, Branson BM, Goldbaum GM, Lockhart D, Kurth A, Rossini A, Wood RW. Choosing HIV Counseling and Testing Strategies for Outreach Settings: A Randomized Trial. J Acquir Immune Defic Syndr. 2005 Mar 1;38(3):348-355
4. Spielberg F, Jackson S. Modeling HIV Testing with the OraQuick Finger-Stick Test: More Effective and Less Costly than Oral Fluid Testing at Bathhouses and a Needle Exchange. 2003 National HIV Prevention Conference, Atlanta, July 27-30, Abstract #971.
5. Wesolowski LG, MacKellar DA, Facente SN, Dowling T, Ethridge SF, Zhu JH, Sullivan PS; Post-marketing Surveillance Team. Post-marketing surveillance of OraQuick whole blood and oral fluid rapid HIV testing. AIDS. 2006 Aug 1;20(12):1661-6.
6. Metcalf CA, Douglas JM Jr, Malotte CK, Cross H, Dillon BA, Paul SM, Padilla SM, Brookes LC, Lindsey CA, Byers RH, Peterman TA; RESPECT-2 Study Group. Relative efficacy of prevention counseling with rapid and standard HIV testing: a randomized, controlled trial (RESPECT-2). Sex Transm Dis. 2005 Feb;32(2):130-8.
7. Branson BM, Handsfield HH, Lampe MA, et. al. Revised Recommendations for HIV Testing of Adults, Adolescents, and Pregnant Women in Health-Care Settings. MMWR. September 22, 2006 / 55(RR14);1-17.
Conflict of Interest:
Dr. Spielberg is currently an outside investigator consulting with OraSure on Over the Counter HIV Testing
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3rd Generation Rapid HIV Test
Submit responseMissed here is the fact that the Uni-Gold test by Trinity Biotech is a third generation rapid test, which means it purported to detect antibodies 4-6 weeks earlier than OraQuick and all other second generation rapid HIV tests.