What is a HIV rapid test?
The Alere Determine™ HIV-1/2 Ag/Ab Combo test used by Anonym AIDS Association screens for HIV-1 p-24 antigen and HIV-1 and HIV-2 antibody. Instead of waiting a week for the test result, the rapid assay’s results are available in 20 minutes – that is why it is rapid.
How does the rapid assay work?
Two drops of blood are collected painlessly by finger prick with a simple disposable device. Until the assay’s result is available the clinic staff counsels the individual on the risks of HIV and other sexually transmitted diseases, the accurate length of the window period of tests and answers any queries.
Does the window period of the rapid assay equal with a standard laboratory test?
Yes, though the exact time is hard to be calculated. According to the users’ manual issued by the manufacturer, the virus titer is high in the first 0-26 days after the infection just as the risk of passing on the virus. Because of that HIV-1 p-24 antigen titer is also high which can be reliably detected by the test in days 12-26. HIV 1/HIV 2 antibodies are mainly present 20-45 days after the infection, and can be accurately detected after this period.
That is to say 28 days, almost a month, should pass after the risk of being infected before you can get a firm result of that particular risk.
Therefore, you should always wait for the window period to pass.
Rapid assays do not establish diagnosis, so if you need a confirmed result, venous blood test must be done in a laboratory.
What does window period mean?
If I had had unprotected sex at the weekend, would the rapid assay detect the infection?
No, it would NOT detect it. The risk and the suspicion of HIV infection is not revealed by the test in the four weeks’ window period. After four weeks the majority of individuals produce enough antibodies, so the infection can be safely detected by the test.
What shall I do if I see any of the signs of STD?
If you have any symptoms of a sexually transmitted disease, or you are worried about a recent “accident”, see the local venereal diseases clinic or the Karolina clinic in office hours or send them an email. If you experience any changes in your body such as itching or any discharge from the urethra, go and see a doctor, have yourself tested and get a treatment if it is needed. The doctor may initiate an immediate treatment if the symptoms are obvious and decides not to wait for the test results. You should abstain from sex for a while, during the medical treatment to avoid passing on the infection.
Based on the above, how accurate are the rapid HIV tests?
They are remarkably accurate with more than 99 %. If the test does not respond, it is a non-reactive result which means that you were HIV negative a month ago taking into consideration the window period.
One of my pals said something like “false or false positive”. What is it? The rapid HIV assay is very sensitive. This enables the test to always respond if there are HIV antibodies in the blood sample. Since the test is very sensitive, sometimes it reacts (it is positive) even if there are no HIV antibodies present. This is the so-called „false positive” result. Basically, this means that if a rapid test is positive, lab tests are needed to be done, though these tests can give clearly negative results. It is quite rare but possible, therefore, we always draw blood sample to run confirmatory tests if the rapid test was positive.
So, if I get a reactive result, should I have a standard laboratory test?
Yes, if your rapid test is positive it needs to be confirmed by venous blood test made in a lab. When it’s done, you have to come back for the results a week later. If HIV-1 antigen and/or HIV-1 and HIV-2 antibodies are present in the sample, a red stripe will appear on the HIV antibody/antigen line area of the test window. If there is no control line the result is invalid. If there is no red stripe in the test window, the test cannot be evaluated, so you need to repeat the test, even if there was a red stripe in any of the test windows. This confirmatory test is done and evaluated by AAA and their lab partner. None of the tests is able exclude the presence of low concentration HIV-1 p-24 antigen and HIV-1 and HIV-2 antibody in a very early stage of the infection.
But does a negative result mean that I am negative?
A non-reactive result means that you were negative up to a month ago. To be always sure about your HIV status, you should try to get tested regularly roughly every 3 month taking into consideration the window period.
More information: Alere Determine™ HIV-1/2 Ag/Ab Combo