References UK clinical guidance from the NHS, the British HIV Association (BHIVA), and the British Association for Sexual Health and HIV (BASHH). Last updated: April 2026.
Yes, you can get most STI tests while on your period. Blood tests (HIV, syphilis, hepatitis) are completely unaffected by menstruation. Urine tests (chlamydia, gonorrhoea) are also reliable during your period, though collecting the sample requires a bit more care.
If you’ve been putting off testing because of your period, here’s what you need to know.
Order a home STI test — do it whenever suits you
Which Tests Can You Do on Your Period?
| Test | Sample Type | Affected by Period? | Can You Test? |
|---|---|---|---|
| HIV | Blood (finger prick or venous) | No | Yes |
| Syphilis | Blood | No | Yes |
| Hepatitis B & C | Blood | No | Yes |
| Chlamydia | Urine or vaginal swab | Minimally | Yes (see tips below) |
| Gonorrhoea | Urine or vaginal swab | Minimally | Yes |
| Herpes (swab) | Swab of active sore | No | Yes (if sore present) |
| Herpes (blood) | Blood | No | Yes |
| Trichomoniasis | Vaginal swab | May be affected | Yes, but swab results slightly less reliable |
| Cervical screening (smear) | Cervical swab | Yes — blood can affect sample quality | Best to wait until period ends |
Tips for Testing During Your Period
Urine tests (chlamydia, gonorrhoea)
- Use a tampon or menstrual cup before collecting the urine sample to minimise blood contamination
- Collect a “first-void” sample (the first urine of the day, or at least 1-2 hours since you last urinated)
- A small amount of blood in the sample is unlikely to affect results, but minimising it gives the lab the best sample quality
Vaginal swabs
- Self-collected vaginal swabs can be done during your period
- The swab collects cells from the vaginal wall, not blood, so menstrual blood doesn’t significantly affect most NAAT tests
- If flow is very heavy, some clinicians may suggest waiting until lighter days
Blood tests
Menstruation has zero effect on blood test accuracy. HIV, syphilis, and hepatitis tests work identically regardless of where you are in your cycle.
The One Test to Postpone
Cervical screening (smear tests) should ideally be done when you’re not on your period. Menstrual blood can obscure the cervical cells the lab needs to examine. If your smear is scheduled during your period, contact the clinic to reschedule for a few days later.
Note: cervical screening checks for HPV and abnormal cells. It does NOT check for chlamydia, gonorrhoea, or other STIs. You need separate STI testing.
Don’t Let Your Period Delay Testing
Waiting for your period to finish before getting tested means another week of uncertainty. For blood-based tests (HIV, syphilis), there’s absolutely no reason to wait. For urine and swab tests, the minor inconvenience of testing during your period is far outweighed by the benefit of getting answers sooner.
If you’ve been exposed to an STI and the testing window has arrived, test now regardless of your period.
Order a home STI test or find your nearest clinic.
Frequently Asked Questions
Can I do an HIV test during my period?
Yes. HIV tests use blood from your arm or fingertip. Your menstrual cycle has no effect on the test.
Will my period affect my chlamydia test results?
Modern NAAT tests are very robust and a small amount of menstrual blood in a urine sample or on a vaginal swab is unlikely to affect accuracy. Use a tampon before collecting your sample if possible.
Can I go to a sexual health clinic during my period?
Yes. Sexual health clinics routinely see patients during menstruation. The staff are professionals and it’s completely normal. Don’t let your period stop you from attending.
Related reading
- Can You Test for STIs While on Your Period?
- Lab-Based Vaginitis Test
- HIV Testing Window Period: When to Test for Reliable Results
- How Accurate Are Rapid HIV Tests?
- Anonymous STI Testing: What It Means
Sources
- NHS — Sexual health conditions
- BASHH — UK clinical guidelines for STI management
- British HIV Association (BHIVA) — HIV treatment guidelines
- Terrence Higgins Trust — sexual health information
- UK Health Security Agency — STI surveillance data
Steve Page is a recognised expert on Sexually Transmitted Diseases (STDs) and STD treatments, having published numerous articles in peer-reviewed journals and presented his research at conferences around the world. He has an in-depth understanding of the latest medical research on STDs, and is an advocate for the development of new treatments and protocols to improve the health of those affected. In addition to his research, he has dedicated his career to understanding the causes and symptoms of STDs, as well as how to best treat those impacted.
