June 2008

Dear Colleague:

The purpose of this letter is to clarify issues that have been raised regarding rapid HIV tests in the June 18, 2008/Vol. 57 MMWR, False-Positive Oral fluid Rapid HIV Tests – New York City, 2005–2008. Findings from this report may raise concerns about the use of rapid HIV tests, especially the use of oral fluid with the OraQuick brand test.

There is no reason to change testing policies or stop using oral fluid rapid tests.

Though New York City Department of Health and Mental Hygiene’s (NYC DOHMH) STD clinics report experiencing as increase in the rate of false-positive test results, this has not been identified as a problem at other sites using oral fluid rapid tests. The Centers for Disease Control and Prevention (CDC) has ongoing investigations, and programs using oral fluid tests should be aware of the unexplained variability in the rate of false-positive tests.

Routine monitoring of rapid testing and a review of false-positive rates should be in place.

Although waived rapid HIV antibody tests are simple to use and can provide reliable results when the manufacturer’s directions are followed, mistakes can occur at any point in the testing process. Additionally, no test is perfect – there may be a small proportion of people who are not infected with HIV who will have a false-positive test result. The product information identifies rates of false-positive results depending on the seroprevalence in the population. Reviewing this information and conducting routine monitoring of testing and false-positive rates will ensure high quality testing outcomes.

Patients/clients should be informed of the strength and limitations of oral fluid rapid tests.

From a user’s standpoint, a pattern of false-positive test results may cause a loss of confidence in the test and can negatively impact services. The CDC recommends that each individual receive the subject information pamphlet as required by the FDA and are properly informed regarding the technology used.

All permitted labs must have a quality assurance program in place.

Quality assurance refers to planned, step-by-step activities that ensures testing is being carried out correctly, results are accurate, and mistakes are identified and corrected to avoid adverse outcomes. These activities should be in place during the entire testing process to monitor staff competency in test performance and the specific procedures that may impact test results (expiration dates, storage and clinic temperature, good lighting, etc.).

All rapid reactive test results require confirmatory testing.

The standard HIV testing algorithm in the U.S. consists of a screening test, such as a rapid test, followed by confirmatory testing (e.g., a western blot). Any rapid reactive test must be confirmed. If such confirmatory testing yields negative or indeterminate results, follow-up testing should be performed on a blood specimen collected four weeks after the initial reactive rapid HIV test result.

Rapid HIV testing continues to play an important role in HIV prevention and is a tool for identifying HIV infection.

Rapid HIV testing, particularly with oral fluid specimens, has increased the availability and acceptability of HIV testing among populations at high risk for HIV infection. A benefit of rapid tests is the increased receipt of test results among those tested. Overall since FDA approval of the oral fluid rapid test, it has performed well despite these episodic elevated levels of false-positive results, and had made HIV testing possible in many venues where performing phlebotomy or finger stick is impractical.

Information on rapid HIV tests and the MMWR can be found at: http://www.cdc.gov/hiv/topics/testing/rapid/index.htm. Product and performance information can be found at http://www.orasure.com/. The New York State Department of Health is encouraging all organizations that conduct oral fluid rapid tests to notify OraSure Technologies of any irregularities in results and/or contact Mara San Antonio of the AIDS Institute, at 1-518-474-3671 for technical assistance.

Sincerely,

Humberto Cruz

Director, AIDS Institute

Links:

Download this letter as a PDF

CDC.gov: Issues with Oral Fluid Rapid Tests

MMWR: False-Positive Oral Fluid Rapid Tests, New York City 2005-2008

MMWR: Revised Recommendations for HIV Testing of Adults, Adolescents, and Pregnant Women in Health-Care Settings