Question:

I'm confused regarding all the conflicting info on HIV Antibody Test Windows. What is the accuracy of an EIA test taken at 4 weeks? What is the accuracy at 6 weeks? What is the accuracy perecntage at 4 weeks, 6 weeks, etc? What is the no kidding recommendation for being able to put some confidence behind an HIV Antibody test? If not confident in the result, what other test can be taken to give a definitive answer regarding infection? Can you please clarify?
--Confused

Answer provided by:

Ross Slotten, M.D.
Klein and Slotten Medical Associates
Private Practice in Family Medicine
With a special interest in HIV disease

I am not prepared to give you statistics about the per cent of individuals who become HIV-antibody positive 4, 6, 8 weeks, etc. after a primary infection. Certainly by three months, the vast majority of infected individuals will have a positive antibody test; and at 6 months, virtually everyone. The test is a three-stage process, if there is a positive result. First, the lab performs what is called an ELISA test. If this is positive, the lab repeats the test a second time. If that test remains positive, then a second type of test is done, called a Western Blot test, which is technically different from the ELISA test. If that is positive, then the person has been infected with HIV. Current HIV testing is both sensitive and specific--that is, there are few false negatives and few false positives when you are testing a population with a high incidence of HIV. So, in the United States, if you are screening gay men or people with a history of IV drug use, the test is extremely accurate. If you are testing the general population, you are probably going to have some false positive tests. This happened a number of years ago in Illinois, the state I live in. During the late 1980s, it was mandated that all people applying for marriage licenses be tested for HIV. Several non-infected women were reported as positive. It's a complicated concept to explain--it belongs to the area of statistics.

If someone has a positive HIV-antibody test, one can perform other tests to prove that someone is indeed HIV-positive. There is the so-called viral load test, which estimates the amount of virus in a person's blood. More than 95% of people infected with HIV will have detectable viral levels (if they're not being treated with HIV drugs). Some people, however, can control their infection without medications, but these are a minority of individuals. One can also culture the virus--but this is a technique that is difficult to obtain outside of research laboratories.

I hope this answers your question.

070307
ASKD070303

AEGiS is a 501(c)3, not-for-profit, tax-exempt, educational corporation. AEGiS is made possible through unrestricted grants from Boehringer Ingelheim, Bridgestone/Firestone Charitable Trust, Bristol-Myers Squibb Company, Bristol-Myers Squibb Company, Elton John AIDS Foundation, John M. Lloyd Foundation, Roche and Trimeris, John M. Lloyd Foundation, the National Library of Medicine, Roche and Trimeris, and donations from users like you.

AEGiS presents published material, reprinted with permission and neither endorses nor opposes any material. All information contained on this website, including information relating to health conditions, products, and treatments, is for informational purposes only. It is often presented in summary or aggregate form. It is not meant to be a substitute for the advice provided by your own physician or other medical professionals. Always discuss treatment options with a doctor who specializes in treating HIV.

Copyright ©1980,2007. AEGiS. All materials appearing on AEGiS are protected by copyright as a collective work or compilation under U.S. copyright and other laws and are the property of AEGiS, or the party credited as the provider of the content.