Here are some instances that would prompt a screening test:
You’re sexually active. Everyone who is sexually active (even if you’ve only ever had one partner and always use protection) should be screened at some point. We recommend an HIV test for everyone who is sexually active. We also suggest women obtain a test for gonorrhea and chlamydia, because, unlike men, they frequently harbor these infections without developing symptoms. Keep in mind that if you’re practicing safe sex and are in a monogamous relationship, you can get tested less frequently. You’re having unprotected sex. If you’ve had or want to start having sex — vaginal, anal, or oral — with a new partner, without a condom, it’s a good idea to get tested. Here’s how long after exposure we can get a reliable test result: 2 weeks: gonorrhea and chlamydia (and a pregnancy test too!) 1 week to 3 months: syphilis 6 weeks to 3 months: HIV, hepatitis C and B
(You might be asking, “What about herpes?” We don’t recommend screening for the herpes virus for most people unless you have an outbreak of sores.)
You’re involved in riskier relationships. If your partner has a chronic or long-term infection, such as HIV or hepatitis C or B, it’s important to be tested more frequently. If you’re in an open relationship, or you aren’t sure that your partner is monogamous, those are also reasons to be screened regularly. Generally, that means about every 6 months or more depending on your personal situation.
You engage in high-risk sexual behavior. High-risk behavior includes intimate contact with a sex worker, IV drug user, men who have sex with men, and having multiple partners, or anonymous partners. In these cases, you’re at higher risk for coming into contact with HIV and hepatitis C, along with syphilis, gonorrhea, and chlamydia and should get tested after contact (remember, that includes oral and anal sex, too!)
You’ve had an infection in the past. You may be more likely to have in infection again, so it’s a good idea to be screened, about 3 months after you’ve been treated, if you are sexually active.
You’re a baby boomer. Because many baby boomers (people born between 1945 and 1965) may have contracted hepatitis C before we even knew the virus existed and could test for it, and because they may have no symptoms of infection, we recommend all baby boomers be tested once for hepatitis C.
You have symptoms. This is a good time to have a discussion with your health care provider. Your symptoms and history will allow you to make the best choice about the most informative tests to look for possible causes of your symptoms.