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.
