Q and A

Question

Is a HIV test accurate at 18 days?

20 September 2010. Related: All topics, HIV testing.

Hello,

I had an exposure nearly 3 weeks ago, I wanted to get tested next Thursday at the 28 day mark. However stupidly I did something else 1 week ago. If I took my HIV test 15 days after an exposure that would not show anything would it? If I took it 18 days then confirmed it with another one after 2 weeks would that give me a good indication for my latest exposure?

Answer

Answer: Charlotte Walker

Thank you for your question.

A test earlier that 28 days will no do you any harm, but it is not sensitive to tell you very much.

The fourth generation HIV tests will detect 95% of infections 4 weeks after an exposure. A fourth generation test 12 weeks after the exposure is needed to rule out the small chance that you take longer than 4 weeks to develop HIV antibodies.

For more information on HIV tests please follow this link

16 comments

  1. miguel •

    recently i was with a girl i penetrated her for about 3 seconds unprotected while she wasnt moist. however i am going crazy out of my mind, because from what she tells me the last HIV test she taken was about 18 months ago which was negative. but at the time was in a relationship where she and her at the time boyfriend where having unprotected sex. since her break up she hasnt taken an HIV test since. now im worried even though i took a oral rapid test yesterday 3weeks after the incident and was negative how accurate are these test. im going crazy over her…

  2. bala •

    Thanks Much

  3. Charlotte Walker •

    If your test results are negative then you do not have HIV. There is no connection between these results and your lesion. You do not need to test again.

  4. bala •

    Hi

    I again tested for HIV and STIs, all came back negative, but also I got oral ulcer (doctor advised pre-cancerous lesion and advised to remove my wisdom teeth), please advice me about my HIV test after 3 1/2 months, is it conclusive or delayed seroconversion? Is there any connection with the HIV test and the lesion?

    Please reply to me

  5. Charlotte Walker •

    This test is accurate. You do not have HIV. You do not have to re-test.

  6. bala •

    Hi,

    I will be glad if I got an answer to my situation below:

    I had unprotected sex (2 times in same day about 30 minutes with sexworker) I tested on the 40th day (5 weeks and 4 days) with an ELISA test and my result was HIV non-reactive). The doctor’s advice is its conclusive. Please advise if the result is accurate.

  7. Charlotte Walker •

    Hi Philip,

    This is where it all gets a bit tricky. Everyone tries to tie it down to on day 17 it is not conclusive but on day 18 it is. Unfortunately this is not the case as when the test is conclusive depends on so many different factors. Some people have found they get conclusive positive results after 14 days. Others can take 20 days or more. Over 95% of people have conclusive tests at 28 days. The vast majority are conclusive at 21 days. A very few people are not. For a graphical example of what I am trying to explain please follow this link. Your 18 day test should be conclusive, however, if you are really worried test again at 28 days.

  8. philip •

    Okay thanks for the advice. Just wanted to ask on the website here there have been a few questions asked if a test done at 18 days is good – and the reply has been conclusive. Is this right? Thanks

  9. Charlotte Walker •

    3-4 weeks after exposure is 21-28 days. So 2 weeks after the 18 day test would be conclusive. You may get an indicator result after 2 weeks but it would not be entirely conclusive.

  10. philip •

    2 weeks after the 18 days or 2 weeks after an exposure? Thanks