HIV combo test question

[Ems_90]

Hi. My question is a bit different than what most people ask. Id like to know that does the HIV1/2 ag/abs combo test detect old hiv infections too? if somebody was infected years back and had no other exposure after that but they got this test now, would it pick up the old infection? I know it checks for antigens and antibodies but antigens disappear after a few weeks, so in that case to check if someone has an old hiv infection or not one would rely on the antibody part of the test correct?
Also, I have read there are different types of antibodies related to hiv, something like IgM etc. Now can I be sure that this combo test will look for all types of antibodies related to HIV or does it not cover all antibodies?
In my country they only have this combo test, I have asked two reputable labs and they told me they only have one hiv test and it is the ag/ab combo test.
So to recap, does it check for old infections assuming no other recent exposure?
And will it check for all hiv antibodies?

[AnxiousNoMore]

Ag/ab is 4th generation test and the latest and it only needs to find one of the 2 markers, It is conclusive any time after 28 days no matter how long you waited, so nothing else to add regarding all your other questions.