STDs can be detected in both blood and urine tests. The STDs that can be detected by blood tests are herpes and syphilis. The herpes simplex virus, both HSV1, and HSV2 can be screened through a blood test. While a blood test can determine if you have contracted the virus and what kind of herpes do you have, it cannot tell if where you are infected in the absence of sores. On the other hand, a blood test for syphilis can determine if you have the virus and if you have already been infected before.
