Blood tests are currently used to diagnose HIV, genital herpes, and syphilis. STD testing may also involve urine testing or taking swabs of the inside of the mouth, anus, the affected area, or sores.
A sample of blood is taken via venipuncture, dry blood spot, or capillary draw, and sent to a lab for testing. Lab technicians run tests on the sample to detect HIV-1 and/or HIV-2 antibodies. The presence of antibodies means the virus is also present.
An IgG test for genital herpes is an immunoglobulin test that reveals how well your immune system is working by showing if immunoglobulin levels are too high or too low. Levels that are too high may indicate a past infection. However, the results of the blood test are not always conclusive. You may have to undergo genital swab testing of the affected area if symptoms are present.
Two blood tests are currently used to diagnose syphilis: rapid plasma reagin (RPR) and venereal disease research laboratory test (VDRL). RPR is the standard test for syphilis. Both tests look for syphilis antibodies. These antibodies are the immune system’s response to the infection.
How to Get Tested in Person and Online
In-person testing is available through your healthcare provider and, typically, a local health department. Online testing for STDs is another option from companies like Nurx. You can purchase home STD testing kits from some pharmacies. These tests require sending blood samples, collected at home, to the participating lab. Results may be delivered via email, companion smartphone app, or by phone.