This is a message from UK to worried wells. My goal is to inform them regarding to window period in UK.
I have been exposed to HIV (unprotected sex) four weeks ago. I went to a GUM clinic (google it: 56 Dean Street London) and was tested at 28th day: negative. I deliberately asked the doctor my next appointment for re-testing. She told me that they and other two GUM clinics they are connected never test patients after 4 weeks as the new window period is 28 days with 4th Gen. testing mechanism. I asked 3 months issue. She advised me not to expect the same window period with 2nd gen and 4th gen tests.
Well, you have to wait 1 week for an appointment from the three GUM clinics I mentioned. This means that, they are extremely busy and they explain the same thing to hundreds of people every week. They would not do that if they could not be totally sure.
You will find many statements on 3months window period. This is normal because these are global, huge organizations taking account of every single individual who lives in, for instance, a country that uses 1st gen hiv test.
I hope this helps.
Hi there and thank you for your comment
It is true that most HIV specialists and medical professionals will suggest a shorter window period for 4th generation testing as this test is a combination of both the P24 antigen and the antibody test and is able to detect the HIV virus in an earlier time frame. The P24 antigen can be detected within 72 hours after exposure if transmission has occurred, so usually a negative test result at 6 weeks can be considered conclusive by many professionals.
The official guidelines for testing in BC, Canada are 4-6 weeks, and up to 3 months (http://www.bccdc.ca/dis-cond/a-z/_h/HIVAIDS/overview/default.htm)
The official US Guidelines are to re-test at 3 months following a high risk exposure (unprotected sex or sharing needles): http://www.cdc.gov/hiv/topics/testing/resources/qa/index.htm
The official UK Guidelines recommend: "Although fourth generation tests shorten the time from exposure to seroconversion a repeat test at three months is still recommended to definitively exclude HIV infection" (http://www.bashh.org/guidelines - scroll down the page and click on the HIV Testing Guidelines 2008 to read the more of the pdf)
As you've mentioned, testing guidelines are recommended globally and health organizations do want to account for those individuals who are still using the older versions of the tests or perhaps have health or medical conditions (such as undergoing chemotherapy) in which case they might be recommended they re-test at 3 or 6 months. As we are not medical professionals, we cannot suggest a 4th generation test at 4 weeks is considered conclusive and definite, only that HIV specialists will often take a negative result at 6 weeks to be conclusive. For those of you who feel strongly about re-testing at 3 months, I would suggest that you either try a different clinic if the GUM clinic is not testing after 4 weeks.
AIDS Vancouver Helpline Volunteer