Brief Answer:
HIV screening ELISA to be done and may be repeated

Detailed Answer:
Hi,

Thanks for writing to us,

HIV as you already know is a sexually transmitted disease where the risk is associated with sexual intercourse, anal intercourse, transfusion of blood or blood products etc. I am glad that you have taken a decision to seek medical advice.

There is an increased risk of transmission associated with unprotected receptive anal intercourse compared to the risk associated with receptive vaginal intercourse.

Intercourse not only has risk of transmission of HIV but also other sexually transmitted diseases like Hepatitis B, Gonorrhea, chlamydia, herpes, syphilis etc. You will need to get yourself tested for these too. Also get yourself evaluated by a doctor for any genital lesions etc.

The standard blood tests done to detect HIV infection is ELISA where the virus is identified >99.5%. If ELISA is negative then the test maybe repeated in 3-6 months. Only if positive, then the confirmatory test- western blot test is used. This is the guideline that is used. Only in case of persisting high risk behavior it is repeated in 3-6 months not otherwise.

The window period or the time taken from infection to virus detection in test extends not more than 6 months. Get the other STD tests done as well.

Direct detection:
The simplest of the direct detection tests is p24 antigen capture assay. Other tests to measure and monitor HIV RNA in blood are reverse transcriptase PCR (RT-PCR), Branched DNA assay (bDNA) and nucleic acid sequence–based amplification (NASBA). These are done when ELISA and western blot tests yield indeterminate results (not when they are negative).

I hope all your queries are answered,
Write back in case of any doubts,
Wishing you best of health,
Dr A. Rao. Kavoor

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Brief Answer:
Wait for 3 months and get ELISA done

Detailed Answer:
Hi,
Thanks for writing in with an update.

I will answer your queries as follows

1. I will get the standard test done at the appropriate time (3 months from exposure). However, in the meantime would you advise going for a early detection test such as PCR.

I will suggest you to wait 3 months and then go for standard tests. This will pick up antibodies. Let me stress here, most lab tests are not 100% confirmatory but they are highly accurate. ELISA is not 100% sensitive in any stage. Only when ELISA is positive confirmatory tests are done. Also in case of ambiguity like - once ELISA positive and once negative, a confirmatory test is done.

2. I am basically very anxious and waiting 3 months for the ELISA would be difficult. If I go for the early detection test and they are negative, would that mean that in likelihood I am HIV-negative. Also, when should I go for the early detection i.e. no. of days from exposure.

You need not be anxious in waiting 3 months for ELISA test. Please go for HIV counselling if you feel it necessary.

It is true that if you go for early detection test and if they are negative, there is still a possibility of being infected. Following Seroconversion – the virus enters the body followed by development of detectable specific antibodies to virus in the blood as a result of infection. These antibodies are detected by the test. This can take a few months where the screening tests can be negative because the antibodies are not detected till seroconversion takes place (known as window period). The window period or the time taken from infection to virus detection in test extends not more than 6 months and this is the reason that a wait of at least 3 months from probable date of exposure is necessary.

I hope all your queries are answered,
Write back in case of any doubts,
Wishing you best of health,
Dr A. Rao. Kavoor

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