Test smart, not big
Many people believe the best STI check is the package with the longest list. CDC guidance instead recommends choosing tests that match each person's symptoms, exposure sites, age and risk.[1] The biggest panel is not always the most appropriate.
Targeted testing finds infections that are actually present, reduces cost and avoids worry over results that would not change care.
Why screening matters
Many STIs cause no symptoms, especially chlamydia, gonorrhoea in the throat or rectum, and latent syphilis. People can be infected without knowing, pass infections on unintentionally, or develop complications later, such as infertility.[1]
Testing the right sites at the right time is far more useful than testing indiscriminately without a plan.
How common are STIs?
The World Health Organization estimated that in 2020 there were about 374 million new infections with four curable STIs, chlamydia, gonorrhoea, syphilis and trichomoniasis, among people aged 15–49 worldwide.[5] This is incidence, not the number of people currently infected, but it shows how common these infections are.
Why several sites may need testing
Gonorrhoea and chlamydia infect only the sites exposed, such as the genitals, throat or rectum, and often cause no symptoms. A urine test detects only urethral or genital infection; it does not replace throat or rectal testing.[1],[2]
People who have oral or anal sex should therefore have throat or rectal samples taken too, which they can often collect themselves.
A sensible baseline set of tests
Test selection starts from your exposure history. Typically it includes[1],[2]:
- Blood tests for HIV and syphilis, with hepatitis B and C considered according to risk.
- Gonorrhoea and chlamydia NAAT at the exposed sites: urine or vaginal swab, throat and rectum.
- Attention to window periods. Testing too soon after a risk may miss infection, so repeat testing may be needed.
Anyone with symptoms such as burning on urination, discharge or unusual vaginal discharge needs symptom-directed assessment and treatment.[4]
How often to test, and what not to test
Frequency. People at higher risk, such as PrEP users or those with several partners, may benefit from testing every 3–6 months. Others may test yearly or after a new risk. Frequency is individual.[1],[3]
Tests not recommended routinely. Screening people without symptoms for organisms such as Ureaplasma or Mycoplasma hominis, and blanket HSV blood testing in people without symptoms, are not recommended, because results rarely change care and can cause needless anxiety.[1],[2]
A good question before any test is: “How would a positive or negative result change my care?”
How we care for you at Dr. Kris Clinic
We choose tests based on your actual risk history, not one package for everyone. History-taking is confidential and judgement-free, so the right sites can be tested, and you can collect throat or rectal samples yourself in a private room, in English or Thai.
When results arrive, we explain them and start treatment promptly if needed, including help with partner notification and retesting. For PrEP users, STI testing is built into every follow-up visit.
Frequently asked questions
My urine test was normal. Does that mean I'm clear?
Not always. Urine testing does not cover the throat or rectum, so test the sites you were exposed at.
How often should I test for STIs?
It depends on your risk. Some people test yearly; those at higher risk may test every 3–6 months.
Why not check for herpes with a blood test?
In people without symptoms, a blood test cannot show when infection happened and rarely changes care. If you have a sore, it should be swabbed directly.
Should I test immediately after a risk?
It depends on the infection; some need time before they can be detected. If you had an HIV risk within 72 hours, seek PEP assessment first.
Choose tests that answer a real clinical question, with a plan for follow-up.[1] Test the sites you were exposed at, at the right time, and get symptoms assessed promptly.
Talk to a doctor about this
Confidential care in Surat Thani, the mainland gateway to Koh Samui, Koh Phangan and Koh Tao. Tue–Fri 17:00–20:00 · Sat–Sun 10:00–15:00 (UTC+7)
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Dr. Krida Uakridathikarn (Dr. Kris)
Board-certified family physician with certificate training in clinical sexology and sexual medicine. He works at Suratthani Hospital and provides sexual health, hormone and LGBTQ+ inclusive care at Dr. Kris Clinic. Profile and CV
References
- CDC STI Guidelines: Screening Recommendations
- CDC STI Treatment Guidelines (2021; current online guidance)
- CDC HIV Nexus: Clinical Guidance for PrEP (current page)
- CDC STI Guidelines: Urethritis and Cervicitis
- WHO: Sexually transmitted infections; estimates for 2020/2022
Keep reading
Main guide: HIV & STI prevention
Syphilis: Symptoms, Testing and Stage-Based Treatment
Gonorrhoea and Chlamydia: Symptoms, Testing and Proper Treatment
Genital Herpes: Symptoms, Testing, Treatment and Living With ConfidenceThis article is general education, not personal medical advice or a promise of results. Diagnosis and treatment require assessment by a doctor. Content reflects the cited sources as of the update date.