Q and A

Question

Is a negative HIV test four weeks after PEP okay?

Good day.

Is it possible to test positive after testing negative after completing 28 day of  PEP?

Answer

Hi

In the UK, people need to wait 4 to 6 weeks after the last dose of PEP before taking a 4th generation HIV antigen/antibody test.

If this test is negative after 6 weeks, then someone is told they do not have HIV. If it is negative after 4 weeks, it means HIV is unlikely, but that a second test should confirm this after a few more weeks.

There is no point taking an HIV test as soon as you finish PEP.

This is because the PEP could just be covering up or delaying a potential infection.

This answer was updated in June 2023 from a question first posted in November 2020. This is because UK guidelines now recommend testing after 6 weeks rather than after 4 weeks.

277 comments

  1. Shaun

    Hello Doc, i had unsafe sex on the first of May and started pep on the 3rd .After completing my 28 days treatment I tested negative .After that we also tested the partner with an Oral test she was negative. But since last week i have been experiencing some weird symptoms. Am I being at risk . I want to take another test.

  2. Simon Collins

    Hi Reelwoon, please see this link on PEP and testing afterwards:
    https://i-base.info/qa/factsheets/pep-faq

  3. Reelwoon

    I have test negative again after 2 weeks of last pep, and am scared? Advice please

  4. Simon Collins

    Hi Test

    Please see the info here on PEP that includes testing:
    https://i-base.info/qa/factsheets/pep-faq

    And here for general info on HIV and testing:
    https://i-base.info/qa/11844

  5. Test

    Hello ,

    I had exposure on feb 8th but I used condom . But since I am not sure about condom breakage , I started using pep from feb10th completed it for 28 days . I took one hiv rapid test after 3 weeks of pep it came negative and took another rapid test at 80 days after completing pep and it came negative . Do I have to another test or I am good ?

  6. Simon Collins

    Hi Anonym, please see this factsheet on PEP which answers your questions about testing afterwards:
    https://i-base.info/qa/factsheets/pep-faq

    thanks

  7. Anonym

    Hi Josh,

    Recently I just received 4th gen test with negative results. This was 42 days after last dose of PEP. Nevertheless, now i experienced diarrhea and urticaria. This could be potentially side effect of SSRI (escitalopramum) which i currently take. Is there still a chance for ARS to appear after 6 weeks from last PEP?

  8. Josh Peasegood

    Hi Francis, yes the 4th generation test you have done is conclusive. You are HIV negative and no further testing is required.

  9. francis

    Hello doc,I have taken a both a rapid 3rd gen test and then a 4th gen lab test ab/ag ,8 weeks after pep.Is it conclusive?

  10. Simon Collins

    Hi Rohit, nothing you describe is a risk for HIV. You didn’t need PEP and you didn’t really need to test. Please see this link for more info:
    https://i-base.info/qa/11844

Comment

Your email address will not be published. Required fields are marked *