Various studies have investigated how long it takes from when genital herpes symptoms show up to when an individual tests positive on a blood test for HSV-2.
As it turns out, the range varies a great deal. This is true both between studies and between tests. For example, the median time from symptoms to a positive HSV-2 blood test was:
HerpeSelect ELISA - 21 days for people who were HSV-1 negative and 23 days for people who were HSV-1 positive
Western Blot - 40 days for people who were HSV-1 negative and 47 days for those who were HSV-1 positive
Western Blot - 68 days
Kalon ELISA - 120 days
Focus ELISA - 21 days
The truth is, it’s usually even longer than those numbers above. Remember, it usually takes around two weeks for symptoms to show up. Therefore, it’s probably a good idea to wait at least a month or two before even considering getting an HSV-2 test after a potential exposure.
Even then, you might want to consider getting retested after six months. It’s also important to remember that the numbers provided above are for people who have had symptoms. Scientists have no clear way to know if the time to a positive test is shorter or longer for those people who are infected without symptoms developing.