Test well outside window period
Hi there,
I performed a test well outside of the window period (over 6 months) that was clearly negative (clear control line only) following a high risk exposure and what i believed to be HIV specific symptoms (seroconversion illness 3 weeks after exposure, then felt well for a few months then lots of symptoms such as reactive arthritis, tarsal tunnell, severe gum disease, cold sores, itchy skin/dermatitis). I didn’t take PEP nor am i on PrEP.
If this was a false negative would another Biosure have same result? Could it be that for some reason my infection can’t be detected by this specific test? In which case should i do a test that is analysed in a lab for 100% certainty or is my result conclusive?
Also, a number of people ask regarding possibility of false negatives outside the window period and they are told that their results are conclusive? Given that the reliability of the rest isn’t 100% how can you be sure?
Thanks in advance
Becky, BioSure UK Ltd
Work on 22nd March 2021
Hi Davy85,
This percentage does not change. The test will always be 99.9% specific but the likelihood that someone receives a false negative result depends on whether their body has produced enough antibodies for the test to be able to accurately detect infection yet. Kindest regards, Becky.
Becky, BioSure UK Ltd
Work on 22nd March 2021
Hi Advice Welcome,
The clinical specificity of the BioSURE HIV Self Test is 99.9%. This essentially means that on average 999 in every 1,000 negative results will be correct. If you were to perform another test under the same conditions, and the result was negative, then there is an extremely low chance that both of your negative results are false. Lab tests are not necessarily more accurate. Individuals who have had recent risky exposures and are very worried about their status are recommended to get a 4th generation test done as the window period of these tests is 4 weeks instead of 12 weeks. Your negative result at 6 months is reliable and conclusive.
False negatives occur most often when users test inside the window period; if not enough antibodies have been produced at the time of testing then the ability of the test to be able to detect them is lower. Even though the test is not 100%, it has been proven to be able to accurately detect infection on 84 days. A negative result can be considered as conclusive at 84 days and the user does not need to retest unless they have another risky exposure. I hope this helps, if you have any other queries, please feel free to leave them below. Kindest regards, Becky
Davy85
Used on 21st February 2021
Hi there. Does the 99.9% reliability at 3 months change the further outside the window period you get? Eg 6 months/a year post exposure etc?
