1. Technically to be an STD you just have to be able to pass the disease through contact with semen or cervical discharge; thus testing for STDs by swabs of the cervix or penis is thought of the best way to check for an STD, but some conditions have to be screened for by blood testing thus you should come in for a visit.
2. The most common STDs can be tested by urine in men or women, and in a culture of the vagina or cervix.
3. Blood testing for STD tests for various types of infections including syphilis, HIV and the various forms of Hepatitis. Even herpes can show up on a blood test.
4. We have to be more vigilant about testing for Hepatitis C as over 3 million in the US have it, and the majority of those with the condition do not know they have it. Hepatitis C is one of those conditions that can go unnoticed in the early asymptomatic stages.
5. According to the CDC if you are a Baby Boomer, born between 1945 and 1965 you need Hepatitis C testing. Even many people with the potentially fatal, but mostly curable, disease Hepatitis C in pregnancy, do not know they have it. In the new CDC guidelines they mention, that just being tested before may still mean you need special blood tests to see if you have cleared the virus.
6. .So ask your gyno which blood tests you need, and how often you should be retested.