Research focuses on rapid HIV testing

Is rapid HIV testing in use in your family planning facility? Findings from a 2007 survey conducted by the National Alliance of State and Territorial AIDS Directors Rapid point to "yes" 94% of health departments indicated they use rapid HIV testing as part of health department-supported HIV testing programs.1

Results from a recently released study indicate that the OraQuick Advance test (OraSure Technologies, Bethlehem, PA), when conducted on oral fluid in a low-prevalence emergency department population, might lead to a high rate of false-positive results.2

In the study, researchers at Brigham and Women's Hospital (BWH) in Boston report that out of 849 adults tested with the oral rapid HIV test, 31 had reactive results. Five patients were truly HIV-infected upon confirmation. Investigators found 84% of positive rapid screening tests turned out to be false when further testing documented that the patient did not have HIV infection.2

The news follows recent reports regarding similar false-positive readings from the New York City Department of Health and Mental Hygiene. Between October 2007 and April 2008, the agency documented a higher-than-usual percentage of false-positive oral HIV tests in its sexually transmitted disease (STD) clinics, with the false-positive rate reaching 1.1% in some months.3 While the rate is below the Food and Drug Administration (FDA) threshold of 2%, it is higher than expected.

In a statement issued to Contraceptive Technology Update, OraSure officials say that test accuracy rates remain within the FDA-approved and expected range of performance, based on monthly data from "hundreds of thousands of tests" conducted annually in New York and around the nation.4 However, the company states it takes every customer inquiry or discordant situation very seriously and is working closely with BWH and the New York City health department to resolve any concerns about the performance of the test.

Review the study

To perform the current study, BWH researchers recruited adults without known HIV disease who were patients at the hospital emergency department. Investigators collected oral samples from the patients and processed them in the emergency department laboratory, where they were read within 20-40 minutes. If results were negative, patients received no further testing for HIV; if results were reactive, patients had a blood test to confirm HIV infection. Confirmatory tests included a serum enzyme-linked immunoassay, a Western blot test, CD4 (cluster of differentiation 4) count, and plasma HIV-1 RNA (ribonucleic acid) level.

Researchers then examined the number of patients who had both reactive results and confirmed HIV infection. Of the 849 adults included in the study, 39 had a reactive rapid oral HIV test. Confirmatory tests showed that five of the 39 patients were HIV-infected, which yielded a 0.6% prevalence rate of HIV infection in the study population. Specificity of the oral test in this setting was 96.9% (95% confidence interval, 95.7% to 98.1%).

Tests key in HIV fight

In 2006, the Centers for Disease Control and Prevention (CDC) called for voluntary HIV screening among all patients ages 13-64.5

Does the CDC still recommend oral fluid rapid HIV tests? Yes, according to information released following the New York report.6 The agency says it continues to encourage the use of oral fluid rapid HIV tests "not only because they allow for testing to be done in many more settings than before, particularly non-clinical settings, but also because they offer the potential to increase the number of persons who are tested and who receive their test results."6

"It is important to note, however, that users need to be aware of the potential for unexplained variability in the rate of false-positive test results and the need to follow a reactive (positive) oral fluid rapid test with a confirmatory test," states the CDC guidance. "Finally, before using any rapid HIV test, patients should be informed that reactive rapid HIV test results are preliminary and require confirmation."

In the United States, there are six FDA-approved rapid HIV tests: OraQuick Advance, Clearview Stat-Pak, Clearview Complete (both from Inverness Medical Professional Diagnostics, Waltham, MA), Trinity Uni-Gold (Trinity Biotech, Bray, Ireland), Reveal G-3 Rapid HIV-1 Antibody Test (MedMira, Halifax, Nova Scotia, Canada ), and MultiSpot HIV-1/HIV-2 Rapid Test (BioRad Laboratories, Hercules, CA). Such tests have been in use for many years in international markets; sensitivity data provided in support of licensure indicate such tests are at least as sensitive as traditional enzyme immunoassay tests.7

Rapid HIV testing represents an expanding field of knowledge; the more providers use these tests in different settings, the more is learned, states Rochelle Walensky, MD, MPH, associate professor at Harvard Medical School and an infectious disease physician at BWH. "We continue to use the OraSure test in the emergency department," says Walensky, who served as lead author of the current study.

With rapid testing, providers need to keep in mind two important points, says Walensky. First, all results should be considered preliminary until they are confirmed, and second, patients should be encouraged to follow up on test results, with providers responsible for facilitating that follow-up, she states. "We offer confirmation testing onsite, and we stay in close contact with the patient so that we can facilitate linkage of care for them," states Walensky.

References

  1. National Alliance of State and Territorial AIDS Directors. Report on Findings from an Assessment of Health Departments Efforts to Implement HIV Screening in Health Care Settings. Accessed at www.nastad.org/Docs.
  2. Walensky RP, Arbelaez C, Reichmann WM, et al. Revising expectations from rapid HIV tests in the emergency department. Ann Intern Med 2008; 149:153-160.
  3. Centers for Disease Control and Prevention (CDC). False-positive oral fluid rapid HIV tests -- New York City, 2005-2008. MMWR 2008; 57:660-665.
  4. OraSure Technologies. Nationwide Data Indicate a Very High Degree of Accuracy for OraQuick ADVANCE Rapid HIV-1/2 Antibody Test with Oral Fluid. Press release. Accessed at phx.corporate-ir.net.
  5. Branson BM, Handsfield HH, Lampe MA, et al. Revised recommendations for HIV testing of adults, adolescents, and pregnant women in health-care settings. MMWR Recomm Rep 2006; 55(RR-14):1-17; quiz CE1-4.
  6. Centers for Disease Control and Prevention. Questions and Answers: False-Positive Oral Fluid Rapid HIV Tests. Accessed at www.cdc.gov/hiv/topics/testing/rapid/oral-fluid_qa.htm.
  7. Paul SM, Martin EG. H IV Test Recommendations, Assay Selection. Accessed at lpn.advanceweb.com/Article.