Does a standard Elisa detect Hiv 2?

Question

Dear Doctor Frascino, This is my second attempt at posting a question. I live in India, approx 8 months ago I had vaginal intercourse with a CSW in Thailand. The intercourse was with a condom. I tested -ve for HIV in Elisa test the results of which were give to me in 30 min. I am unaware what sort of Elisa (which generation) or for what types of HIV it tested for. I have read on some sites that Elisa is not always reliable when it comes to testing for HIV 2 or the rarer HIV 1 subtypes. Infact On another forum a doctor had said that a person with HIV 2 would test positve 80% of the time in a HIV 1 Elisa test. I was hoping you could clear my misunderstading on the subject. I am sure that you are a very busy person and the demands on your time are many. In fell that you must possess the patience of a saint and then some to answer the questions posted to you. I was hoping that you could do me this favour and answer my question.

Regards,

Sam.

Answer

Hello Sam,

The screening tests for HIV-1 and HIV-2 are indeed different. There is some cross-reactivity between these two HIV viruses that accounts for the 80% figure quoted by the other forum doctor. Some HIV tests combine the two tests and run them simultaneously. These are often listed as "HIV-1/2" or "HIV-1 and HIV-2" on the lab test results. I have no way of knowing what type of test you had performed. You will need to check with the doctor or clinic that performed the test.

Good luck.

Dr. Bob