When to be tested for HIV antibodies

Hi, welcome to the ehealth forum and I am glad to help you.
You seem to be concerned by the possible HIV exposure because of unsafe sexual practices. Though a person who is infected with HIV will become infectious very rapidly (within a day or so), he will normally have to wait a while before an HIV test will produce an accurate result. The length of time a person should wait before taking an HIV test will depend on the type of test they are taking.

In the vast majority of cases, the standard test that will be offered at an HIV testing centre will be an HIV antibody test. The HIV antibody test looks for antibodies to the virus in a person's blood. For most people these antibodies take 6 weeks to 3 months to develop. In rare cases, it can take up to 6 months. It is extremely rare for a person to take any longer than 6 months to develop detectable antibodies.

You may go for a second test as you took a test at 168 days after exposure and centers recommend repeat testing at 180 days(6 months) after exposure though the result is likely to be negative.
Hope this helps. Take care.