May
I have a swift question. Suppose someone had an encounter with an infected person about 3-5 years ago. Will the antibodies still show up for the rapid test? Is it okay to test after a few years?
Thank you 
I can not find the right answer to this!
Answer:
The antibody like the virus is kept for life as far as we know.
Edit
We depend on it for diagnosis. That is why the window period is so important in waiting the 6 months needed for antibody production. The initial testing or screening for HIV is antibody testing. Once antibody production has begun then it continues for life. This is especially true if the virus is still present and the exposure to the virus is continuous. With other infections such as childhood viruses the antibody can dwindle and at times undetectable because there’s no continued exposure to the virus.