STI testing is a set of lab tests that check for sexually transmitted infections using blood, urine, or swab samples. There’s no single test that screens for everything at once. Instead, each infection requires its own specific test, and which ones you need depends on your age, sex, sexual activity, and risk factors. Most tests are quick, painless, and can be done at a doctor’s office, sexual health clinic, or even at home with a mail-in kit.
What STI Tests Actually Check For
There’s no universal “full STI panel.” The CDC doesn’t define one standard package. Instead, your provider selects tests based on your situation. The infections most commonly screened for include chlamydia, gonorrhea, syphilis, HIV, hepatitis B, hepatitis C, trichomoniasis, HPV, and herpes. You won’t necessarily be tested for all of these at every visit.
Herpes screening, for example, is not recommended for the general population. It’s typically only offered to people with symptoms, multiple partners, or those already being evaluated for other STIs. HPV screening is done through cervical cancer screening (Pap smears) rather than a standalone STI test, and follows its own schedule: every three years for women aged 21 to 29, and every three to five years for women 30 to 65. HIV screening is recommended at least once for everyone aged 13 to 64.
How Samples Are Collected
The collection method depends on which infection is being tested. Most visits involve one or more of three straightforward methods.
- Urine sample: You urinate into a cup. This is the standard method for chlamydia, gonorrhea, and trichomoniasis.
- Blood draw: A small needle draws blood from your arm. Blood tests diagnose syphilis, HIV, hepatitis B, and hepatitis C. They can also detect herpes antibodies.
- Swab: A provider uses a soft swab to collect a sample from the site of potential infection. For women, this is often the vagina or cervix. For men, the penis or urethra. Swabs can test for chlamydia, gonorrhea, HPV, and herpes, and are especially important for detecting infections at specific body sites like the throat or rectum.
For men who have sex with men, the CDC recommends testing at all sites of sexual contact, including the urethra, rectum, and throat, regardless of condom use. This matters because infections at these sites often cause no symptoms and won’t show up on a urine test alone.
How Long Results Take
Rapid HIV tests can deliver results in about 20 minutes. For other infections, standard lab turnaround times vary: chlamydia results often come back within 24 hours, gonorrhea within one to three days, herpes in two to three days, and syphilis in two to five days. If your provider sends samples to an outside lab, add a day or two for transit. Most people have all their results within a week.
Window Periods: When Testing Works
No STI test is accurate the day after exposure. Each infection has a “window period,” the time between exposure and when a test can reliably detect it. Testing too early can produce a false negative, meaning the infection is there but the test misses it.
HIV has the shortest window with modern blood tests. An antigen/antibody blood test catches most infections within two weeks and nearly all by six weeks. The oral cheek swab version is less sensitive early on, catching most cases by one month but needing up to three months to detect nearly all infections. Syphilis blood tests catch most cases at one month and almost all by three months. Hepatitis B typically becomes detectable at three to six weeks, while hepatitis C can take two months for most cases and up to six months in some people.
Chlamydia and gonorrhea are generally detectable within one to two weeks after exposure. If you’ve had a specific exposure you’re worried about, the timing of your test matters. Testing too early and getting a negative result doesn’t necessarily mean you’re in the clear.
NAAT Testing vs. Antibody Testing
Two fundamentally different approaches power most STI tests. Nucleic acid amplification tests (NAATs) detect the genetic material of the infection itself. They’re the gold standard for chlamydia and gonorrhea because they’re highly sensitive and can pick up very small amounts of the pathogen. Antibody tests, by contrast, detect your immune system’s response to an infection rather than the pathogen directly. These are used for HIV, syphilis, herpes, and hepatitis.
The distinction matters most for HIV. Rapid antibody tests are convenient but can miss people in the earliest, most infectious stage of the disease. Research in high-incidence populations found that rapid antibody-only tests failed to detect 20% of HIV-infected individuals, missing those with acute infections who hadn’t yet developed detectable antibodies. Newer fourth-generation tests that combine antigen and antibody detection close much of this gap, which is why the blood-based antigen/antibody test has a shorter window period than the oral swab.
For syphilis, diagnosis requires two different types of blood tests run together. Using only one type can produce false negatives in early infection or false positives in people who were previously treated. Labs may run these in different orders (called “traditional” or “reverse” algorithms), but either way, a single test alone isn’t enough for a reliable syphilis diagnosis.
Who Should Get Tested, and How Often
CDC guidelines vary by group. Sexually active women under 25 should be screened for chlamydia and gonorrhea annually. Women 25 and older need annual screening only if they have risk factors like new or multiple partners. All adults aged 13 to 64 should be tested for HIV at least once as part of routine care. Pregnant women should be tested for hepatitis B, syphilis, and HIV at their first prenatal visit.
Men who have sex with men face the most comprehensive recommendations: annual screening for chlamydia, gonorrhea, syphilis, and HIV at minimum, with more frequent testing (every three to six months) for those with multiple partners. People living with HIV should be screened for all major STIs at their first evaluation and at least annually after that, including trichomoniasis for women.
At-Home Test Kits
Home STI test kits let you collect your own samples (typically a finger-prick blood spot, urine, or vaginal swab) and mail them to a lab. A 2024 meta-analysis published in Nature found that self-collected specimens showed comparable diagnostic accuracy to those collected by healthcare workers for most STIs. In one study, self-collected samples had 100% sensitivity with 88.9% specificity, compared to 100% sensitivity and 90% specificity for provider-collected samples.
Home kits are a solid option if privacy, convenience, or access to a clinic is a concern. They typically cost between $50 and $250 depending on how many infections are included. The tradeoff is that you won’t have a provider on hand to discuss results or collect samples from harder-to-reach sites like the throat or rectum.
Cost and Where to Go
Most insurance plans cover STI screening with no out-of-pocket cost when it follows recommended guidelines. If you’re uninsured, community health centers and Planned Parenthood clinics use sliding-scale fees based on income. At Planned Parenthood locations, individual test costs for uninsured patients range from $0 to $20 for chlamydia or gonorrhea, $0 to $16 for syphilis, $0 to $64 for herpes, and $0 to $100 for trichomoniasis, plus an office visit fee of $0 to $192 depending on your income.
Local health departments often offer free or low-cost testing, particularly for HIV and syphilis. Many provide anonymous HIV testing, meaning your name isn’t attached to the test at all. For other STIs, testing is typically confidential (your name is on the record, but results are private) rather than fully anonymous. County and city health departments, college health centers, and urgent care clinics are all common testing sites beyond your regular doctor’s office.