Hi doctor. What difference between the analyses IFA and ALISA. I live in Russia and at us do only analyses IFA or DNA. I had dangerous contact 18 months ago and I had all symptoms of HIV infection. Now analyses IFA and DNA are negative but are increased all limphohodes on a body (neck, stomach, under a jaw), high temperature, weakness during one year. Some doctors speak that I have a HIV-infection and that there are situations when the analyses are negative 2 years from the moment of infection. (but seldom) What you can tell. Thank for the answer.

IFA is immunofluorescence assay. ELISA is enzyme linked immunosorbent assay. These are both assays that detect HIV antibodies in blood serum. A DNA test detects presence of the HIV virus not antibodies your body makes against the virus. I cannot comment on the accuracy of the tests in your country. But in the U.S., given the accuracy of our current tests, we have not had documented reports of delayed positive antibody testing.