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how many tests are there for hiv anyway?

Jun 25, 2002

my partner was recently diagnosed with aids and his doctor tested me for hiv. test came back negative and i will repeat in one month then three months then six months. However, i keep reading on this page about different tests. pcr/dna ect...?? i never asked what method of testing was used on me. should he have tested a number of different ways? i'm beginning to become alarmed that one test could come back neg. but i still am infected. my partner and i have been together for 12 yrs and monogomous so they figure he has had it all this time. i just don't understand how i could be negative. should i ask for a variety of tests? thanks for any light you can shed.

Response from Mr. Kull

It's really up to you and your doctor to decide what testing is most appropriate for you. Why don't you consider talking to your partner's doctor about your questions?

Antibody testing is the gold standard for HIV diagnosis. If you are interested in determining your HIV status three or more months after exposure, HIV antibody testing (ELISA/Western Blot) is your BEST option.

PCR (polymerase chain reaction) tests are used to detect the presence of HIV-RNA or DNA in a person's blood. Essentially, PCR tests are looking for evidence of virus itself and not antibodies. These tests are not FDA approved for diagnostic purposes because of higher rates of false positives when compared to the much more specific antibody tests. The p24 antigen test is the only licensed tool for detecting infection earlier than the antibody tests (it is used in screening blood donations), but is not as sensitive as PCR testing for viral RNA. The p24 test is more likely to be falsely negative than PCR testing or antibody testing AFTER the window period because it lacks the other tests' sensitivity.

A recent review of literature on primary HIV infection states that PCR tests for viral RNA can detect infection one to three weeks earlier than the standard antibody test (which is about, on average, 3-4 weeks following infection). Virus has been detected in plasma anywhere from 4 to 11 days following infection. While false positives on viral-RNA tests are uncommon, they are more common than false positives on antibody testing because of the PCR's increased sensitivity and the technical complexity of performing the tests.

PCR tests are most meaningful when a physician is attempting to diagnose symptoms that suggest acute (recent) infection, when viral levels should be high. Otherwise, since levels of virus in an infected person are variable based on immune response, viral characteristics, and type of test used, a PCR test used alone is not sufficient. In your case, since your exposures potentially happened over an extended period of time, antibody testing makes a lot of sense. But PCR testing in conjunction with antibody testing in your case would make sense as well.

This must be an anxious time for you. Try to work closely with your doctor and get the support that you need.


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