Public Release: 

One-step HIV test may be cheaper, faster, less wasteful

Center for Advancing Health

A quick, readily available test for the AIDS virus that offers results in half an hour may not only be faster but also much cheaper than standard tests that take weeks to deliver results, a new study suggests. Using this one-step rapid test also means that clients know their HIV status immediately and don't have to return to the clinic for a later visit.

Donatus U. Ekwueme, Ph.D., of the Centers for Disease Control and Prevention in Atlanta and colleagues analyzed costs of three HIV tests, comparing the standard counseling and testing method to two-step and one-step rapid-test methods. Previous research established that the rapid tests give results as accurate as the standard test.

"The one-step rapid method -- where combinations of rapid tests are used to provide a definitive HIV test result -- was consistently the least expensive of the three methods," Ekwueme says. This was true for both HIV-positive and HIV-negative clients.

The cost of lab materials and staff time per HIV-positive person notified was nearly $82 for the standard test, about $86 for the two-step rapid method, but only $34 for the one-step method.

Their work appears in the August issue of the American Journal of Preventive Medicine.

With the standard test, the client's blood sample is sent out to a central lab for evaluation. If repeated runs of this first test react to HIV antibodies -- indicating presence of the virus -- technicians run a second test, called a Western blot. The whole process may take from several days to two weeks.

"However, with the rapid-testing methods, an on-site test is used for the initial screening and results are available with in minutes or hours," says Ekwueme. "Clients can receive preliminary HIV results on the same day."

If a preliminary rapid test is negative, showing no sign of the HIV antibodies, the client is not infected and testing is complete. If the HIV test is positive, however, further testing must be done to confirm the results. What happens next depends on which of the two rapid methods is used.

In the two-step method, the blood samples are sent from the counseling and testing center to an outside lab for confirmation by the Western blot test. These clients must return for a second visit to receive their final results. Most do return, but not all.

In the one-step process, several different rapid tests are applied to the sample. The final result is determined by which two out of three test results agree. Both HIV-positive and HIV-negative clients thus get their results on the same day, since there is no need to send the samples to a separate lab.

Ekwueme defined costs two ways. The first included costs of materials and staff salaries to the healthcare provider. The second were societal costs -- the provider's costs plus the client's time and transportation.

The researchers then considered the fact that some clients may not return to the center to learn their status. If they don't return, their test is effectively wasted, driving up total costs.

In the end, because it required no return clinic visits or use of the expensive Western blot test for confirmation, the one-step rapid protocol was less costly both for HIV-positive and HIV-negative persons.

While this study was not a cost-benefit analysis of the test methods, Ekwueme says that it should provide useful information to HIV program managers and others who must compare alternative testing programs.

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Partial support for this research came from the National Institute of Mental Health.

BY AARON LEVIN, SCIENCE WRITER
HEALTH BEHAVIOR NEWS SERVICE

FOR MORE INFORMATION:
Health Behavior News Service: (202) 387-2829 or www.hbns.org.
Interviews: Contact Donatus U. Ekwueme, Ph.D., through CDC Media Relations: (404) 639-3286, or E-mail: dce3@cdc.gov.
American Journal of Preventive Medicine: Contact the editorial office at (619) 594-7344.

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