"Is there a blood test that can tell whether I have genital herpes?"
The answer is no and I’ll explain why. Yes, there are blood tests for Herpes Simplex Virus 1 and 2 (HSV1 and HSV2) but they are not recommended in adolescents or adults who are asymptomatic. In other words, if you don’t have a sore that you are worried may be herpes you don’t need a blood test.
Here is why all medical organizations recommend against routine blood tests for HSV1 and HSV2 in people not having symptoms, and why a culture of a sore is the only reliable way to see if you have genital herpes.
• First, the gold standard for diagnosing herpes is a test done on a sore (either a viral culture or PCR testing), not a blood test.
• The most sensitive test for genital herpes is a PCR test done from a lesion or sore and this is readily available now.
• If a PCR test from a swab of a sore is positive, you can be pretty sure herpes is the cause.
What’s the deal in a person who has no sore, but wants a blood test for herpes?
• Blood tests are tests for HSV 1 or HSV 2 antibody
• Both HSV 1 and 2 can cause genital lesions and in fact the incidence of HSV 1 genital infections has surpassed that of HSV 2.
• Antibodies to HSV 1 are very common and many people will test positive for HSV 1 antibodies who will never develop lesions. For HSV 2, twenty- two percent of adults who have never had genital lesions will have a positive blood test for HSV2
• What this means is that HSV 1 and HSV2 antibodies in the blood are frequently seen in people who have been exposed but will never develop either oral or genital lesions and may remain asymptomatic.
It is for this reason that we don’t recommend blood tests for herpes in asymptomatic (no evidence of lesions or sores) adolescents and adults.
Hope that helps.