Hiv p24 ag ab combo test at 28 days, 42 days and 62 days, some are negative.quanto to be safe after 62 days?

Not a good test: P24 antigen testing is not the best way to rule out infection. The most sensitive test is a qualitative viral dna test, not usually performed. At 62 days HIV elisa may well be positive, if you were infected. Because sometimes antibodies are not formed until 90 days, you can complement by HIV RNA test that can detect down to 20 copies per ml of blood.