Human immunodeficiency virus (HIV) is a form of retrovirus that causes HIV infection. Over time it leads to acquired immunodeficiency syndrome (AIDS).
AIDS is a condition where due to progressive failure of the immune system, allows life-threatening infections which don’t usually bother a healthy person and cancers to thrive in the body. This is why HIV is one of the infections we humans are most worried about after a sexual encounter.
There are a few ways to detect HIV in the blood and each method has different testing window periods.
Window period is basically the time between potential exposure to HIV infection and the point when the blood test will give an accurate result.
The most commonly ordered tests in Singapore for detecting HIV are:
- HIV antibody test (3rd generation)
- HIV antigen/antibody test (4th generation).
The HIV antigen, also known as p24, may become detectable in the blood 14 to 20 days after an infection and peaks at about day 30.
On the other hand, the HIV antibodies may become detectable as early as day 20 to 23 but in some cases, it may take longer.
With this in mind, the earliest you can undergo a HIV antigen/antibody (4th gen) test is 2 weeks after an exposure but a repeat test will need to be done at the 4-week mark where the p24 is at its peak and the test is deemed accurate.
The HIV antibody test (3rd generation) test is best performed at the 3-month mark for it to be deemed conclusive.
With these in mind, there are in fact other tests which may be able to detect HIV before the 4 week mark, however, it is very costly and the waiting time to get the results are long and therefore are not usually recommended.
It is therefore best to see a doctor with experience in HIV testing who will be able to tailor the tests to your history. Do note that there are rapid tests available in some clinics in Singapore, that will be able to give you a result in 30 minutes.