Can you take an STI test when you have your period?

I was lying under a blanket, enjoying a chill Friday evening when my phone buzzed. "Hey, you might wanna get tested," the text read.

I sat bolt upright. The message was from the guy I'd been sleeping with. And the test did not refer to a COVID lateral flow. "What do you mean?" I said, my heart pounding in my chest. "I've just found out I've got chlamydia," he replied.

My health anxiety sent me through a loop that night. I immediately went to the Sexual Health London (SHL) website and ordered myself a free STI (sexually transmitted infections) home test kit. My anxiety could only be quelled by taking a test. But the annoying thing was, chlamydia has around a two-week incubation period. The last time I'd had sex with this person was just a few days prior. I looked at my period app and calculated that 14 days from the possible infection date, Mother Nature was also sending something else my way: my period.

The day after getting the text, I realised I needed to do something to stop my mind from going round in circles. Mid-spiral, I went to the pharmacy and bought myself a rapid chlamydia test. It was negative, which gave me some short-lived relief. But I wasn't off the hook — I still needed to wait another two weeks to do a test that could give me more accurate results. I wanted to fast forward through time so I could put myself out of my misery but I had questions. Can you take an STI test when you have your period? Or did I need to wait until my period had ended before taking the test?

STIs are common and anyone who has oral, anal, vaginal sex, or genital skin-to-skin can get an STI. Per Planned Parenthood, nearly all sexually active people get an STI at some point in their life.

I trawled the internet and found little that could tell me definitively one way or another. It was infuriating. I ended up taking five negative chlamydia tests to make sure the result was accurate. If you ever find yourself in the same situation as me, here's what you need to know about having your period when you want to take an STI test.

So, is it possible to take an STI test on your period?

The good news? Yes. Bekki Pickerill, clinical manager at Brook, says you can take an STI test when it's your time of the month. "We advise not to delay getting an STI test, irrelevant of where you are in your menstrual cycle," Pickerill says. "The only thing to be mindful of the incubation periods, for example waiting two weeks post-sex will give you the most accurate results for STIs like chlamydia and gonorrhoea."

According to SHL, "Owing to how sensitive the chlamydia and gonorrhoea DNA testing is, menstrual blood does not typically affect the outcome of the result." From time to time, for unrelated reasons, a swab test may need to be repeated.

Planned Parenthood echoes this, stating it's totally fine and normal to get tested at any point in your menstrual cycle. "Even on your heaviest days. Your period won't affect the results," the advice reads.  

It's important to know that certain STIs take longer to show up in tests — this is because of the varying incubation periods of each conditions. As I mentioned previously, it's advised to wait two weeks before taking a chlamydia test. With HIV, it can take up to 90 days to show in a test, depending on the type of test.

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How can I get an STI testing kit?

If you live in the UK, you can consult the Brook website to find out how to order free at-home testing kits in your area. You can also use their find a service tool to locate your nearest sexual health clinic. You can also check the FreeTest.me website to see if your postcode is eligible for a free postal kit.

If you're based in the U.S., you can access care by booking an appointment with Planned Parenthood. Everlywell has an STI test subscription which costs $14.99 a month and provides you with one of five STI tests.

Nearly all sexually active people will get an STI at some point in their life. Chlamydia is one the most common STIs in the UK and it's usually treated with a short course of antibiotics. It's important to catch it early on because, per the NHS, "If left untreated, the infection can spread to other parts of your body and lead to long-term health problems, especially in women." In women, untreated chlamydia can cause pelvic inflammatory disease (PID), ectopic pregnancy, and infertility.

If you live with health anxiety, the idea of getting an STI is anxiety-inducing, but getting tested is really important.