Which STD Test Do I Need?

There is no single STD test. Each infection is found by a different kind of sample, and the right set depends on the kind of sex you have had and any symptoms you have. Here is how to work out what to ask for.

Which test do I need for chlamydia?

Chlamydia is checked with a nucleic acid amplification test (NAAT), which looks for the genetic material of the bacteria. CDC describes the sample options:

• Urine, for men (first-catch urine is the preferred type).
• A vaginal swab, for women. Patients can collect this themselves, and CDC says self-collected swabs perform as well as clinician-collected ones.
• A throat swab or a rectal swab, if those sites were exposed. CDC says these infections are found by testing at the site of exposure, and self-collected rectal swabs are a reasonable option.

A urine test only reflects the urinary tract and genitals, so it will miss an infection in the throat or rectum. These infections often cause no symptoms.

Do I need a throat or rectal swab?

Include one if you have had oral sex (for a throat swab) or anal sex (for a rectal swab), and check that the test you order includes it.

Which STDs need a blood test?

• HIV. CDC says HIV tests are typically done on blood or oral fluid. The lab-based antigen/antibody test uses blood drawn from a vein. Rapid finger-prick and home tests also exist.
• Hepatitis B and hepatitis C. Both are checked with blood tests. CDC recommends that all adults be screened for hepatitis B at least once, and for hepatitis C at least once in their lifetime.

Your own situation matters too. The right set of tests depends on your age, pregnancy status, the kind of sex you have and your number of partners, which may differ from a friend’s.

For syphilis, check whether it is included in the panel you order, because panels differ. The window periods guide explains how long to wait before each test is useful.

When is a herpes test appropriate?

The most sensitive herpes test is a swab of an active sore, taken with a type-specific test. CDC says a swab from an old or healed lesion, or a swab taken without a sore, can miss herpes, so the sore needs to be present when it is taken. If you have a sore, see a doctor or clinician quickly for a swab.

Without sores, a herpes blood test is not part of routine screening. CDC states that routine HSV-2 blood screening of the general population is not recommended, and that type-specific blood tests are for specific situations, such as recurrent symptoms or a partner with herpes. If you want one, you can order a type-specific blood test online, but weigh up what a result would and would not tell you first. The herpes hub covers swab and blood testing in more detail.

What about trichomoniasis, HPV and other infections?

• Trichomoniasis is checked with a vaginal swab or urine sample for women. CDC recommends diagnostic testing for women with vaginal discharge, and annual screening may be considered for some people at higher risk. Check whether the test you order includes it.
• HPV has no routine test for most people. CDC recommends routine screening only for cervical cancer, and genital warts are usually diagnosed by visual inspection. The HPV hub explains what testing can and cannot show.

How do I decide what to ask for?

Think about three things: the kind of sex you have had, which body sites were involved, and how long ago the exposure was. Then check the test’s details before you order:

1. Does it test for chlamydia at every site I’ve had sex with?
2. Does it include HIV, syphilis and hepatitis B and C?
3. If I don’t have a sore, is herpes testing worth doing?

If you were exposed recently, you may need to test now and again later. The HIV hub has more on testing and prevention, and the guide to what happens at a test walks through ordering and the lab visit.