When your blood is tested for HIV, the lab first performs what is known
as an EIA or ELISA (enzyme-linked immunosorbent assay). A negative ELISA
means that no antibodies were found in the blood and that the person is
HIV-negative. A positive result is confirmed with a second ELISA. If
the second ELISA is positive, a Western Blot must be done to ensure that
the antibodies detected in the ELISA test are really HIV antibodies.
Many health clinics are now using rapid HIV tests instead of the ELISA
test. Rather than sending a blood sample to a lab, rapid testing is done
on the spot and results are available in about 20 minutes. Several
rapid HIV tests have been developed that can test saliva or blood from a
finger prick. The accuracy of rapid tests is similar to ELISA, and
positive results still need to be confirmed by Western Blot.
