Can your period affect STI test results?

STI tests are an important part of preventive healthcare – especially for people with new or multiple sexual partners. They help detect infections early and allow for timely treatment, often before any symptoms appear. However, many people who menstruate ask themselves an important question when preparing for a test: Can my period affect or interfere with the test results?

In this article, you’ll learn whether and how menstruation can influence different types of STI tests – such as swab, urine, or blood tests – and when the best time is to take them.

Table of contents

• What does an STI test check for?
• What types of samples are used for STI testing?
• Can menstruation affect the test results?
• When should you get tested for an STI?

What does an STI test check for?

An STI test checks whether certain sexually transmitted infections (STIs) are present. STIs are infections that are transmitted through sexual contact via bodily fluids or close mucous membrane contact. Many of these infections cause no noticeable symptoms at first – meaning you might not even know you're infected. Without treatment, they can cause health problems and be unknowingly passed on to others. This is why regular testing is especially important.

The most common STIs include:

• Chlamydia

• Gonorrhoea

• Trichomoniasis

• HIV

• Syphilis

• Hepatitis B

• Herpes

• HPV (human papillomavirus)

Source: NHS, 2024

What types of samples are used for STI testing?

Depending on the type of infection and test, different types of samples may be used. The most common methods – especially for at-home testing – include:

• Swab (e.g. for chlamydia, gonorrhoea, trichomoniasis, HPV, herpes)
  → A sample is taken with a cotton swab from a mucous membrane or skin surface – for example, vaginal, anal, oral (throat), or directly from visible skin changes.

• Urine sample (e.g. for chlamydia, gonorrhoea)
  → First-morning urine is collected to detect the presence of pathogens.

• Blood sample (e.g. for HIV, syphilis, hepatitis B, HPV, herpes)
  → A small amount of blood is taken, usually via a finger prick.

Source: MedlinePlus, 2024

Can menstruation affect the test results? 

Whether your period affects an STI test depends on the type of test. In most cases, menstruation is not a barrier to testing.

• Urine and blood tests can be carried out reliably and without issues during menstruation.
• For vaginal swabs, heavy bleeding may slightly affect sample quality, for example by diluting or contaminating the sample with blood. However, most tests still remain reliable even under these conditions.

If you're unsure whether the test can be done during your period, check the instructions included with your test kit or contact customer support. You can also speak to your doctor for advice.

Source: MedlinePlus, 2024

When should you get tested for an STI?

An STI test is especially recommended in the following situations:

• After unprotected sex (vaginal, oral, or anal)

• When you have a new sexual partner or multiple partners

• If a condom broke or wasn’t used properly

• If you notice symptoms in the genital area, such as:

  • Burning or pain when urinating

  • Itching, redness, or unusual discharge

  • Skin changes like blisters, warts, or sores

• If your partner has tested positive for an STI

• When planning a pregnancy or during pregnancy

• As a routine check-up – e.g. 1–2 times per year if sexually active

Testing at the right time can help detect infections early and allow for prompt treatment – before complications arise or others are infected.

Source: CDC, 2025

With Homed-IQ’s at-home tests, you can check your health discreetly, safely, and reliably – without waiting rooms or doctor’s appointments. Your sample is analyzed in a certified lab, and your result is provided confidentially via our secure online platform.