Blood tests are available to diagnose a variety of sexually transmitted diseases, including HIV, Hepatitis B and syphilis. Urine tests are commonly performed to test for chlamydia and gonorrhea. The usual route of transmission for Hepatitis C is via blood, which can occur through the sharing of needles for intravenous drug use or tattoos. Hepatitis C is not commonly transmitted sexually, and as such may not be tested for by a physician conducting a screen for sexually transmitted diseases. A blood test is available to test for Hepatitis C, and if you do have risk factors for acquiring this virus, you should have a discussion with your doctor
and ask for a test to be conducted.