Hello and thank you for your post on e health forum.
From the question, it seems that you want to know if the test results change with the duration of the sickness, and the chances of having a wrong result at any point of time.
Please understand that tests for HIV (ELISA) detect the presence of antibodies to HIV, which usually present within 4 - 12 weeks of exposure, depending on the severity of exposure (Probable no of virions that might have entered the blood stream).
Hence once antibodies are synthesized by the body, they remain in considerable amounts as long as viremia is present.
Hence the chances of very sensitive tests (like ELISA) giving a negative result, in presence of antibodies to HIV, is very negligible.
if antibodies are present - the test is positive, if they are absent - the test is negative. It is as simple as that.
There is no reason to doubt test results if they are done at the correct interval.
The best time to do a ELISA test for HIV antibodies is after 4 weeks of exposure. 90% of normal individuals who have HIV exposure, will seroconvert within 4-6 weeks. The sensitivity of the ELISA test is 99.9%.
If a test once done after 12 weeks of exposure - is NEGATIVE, the chances of developing antibodies to HIV at a later date will be negligible. Hence there is no need to repeat the test again.
Production of antibodies depends on the individuals immune system. Presence of immune disorders that affect antibody production, cause late production of antibodies. But such conditions are rare, and present very early in childhood itself.
Since you are probably, with a normal immune system, you will not have such issues.
Since the latest ELISA test at 12 weeks (3 months) is negative, you are probably HIV negative, and there is no need to test again.
But usually clinicians tend to be cautious and ask patients to repeat the test again and again, causing severe stress and anxiety. But this is not necessary.
"Ask a Doctor" questions are answered by certified physicians and other medical professionals.
For more information about experts participating in the "Ask a Doctor" Network, please visit our
medical experts page.
You may also visit our HIV and AIDS , for moderated patient to patient support and information.
The information provided on eHealth Forum is designed to improve, not replace, the relationship between a patient and his/her own physician.
Personal consultation(s) with a qualified medical professional is the proper means for diagnosing any medical condition.