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.
PCR testing for Trichomonas vaginalis is the most accurate method for diagnosing trichomoniasis. It uses NAAT (nucleic acid amplification testing) on urine or swab samples to detect the parasite’s genetic material. Modern PCR testing has largely replaced older methods like microscopy and culture because it’s more sensitive and reliable.
Here’s what to know.
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How PCR Testing Works
- Sample collected (urine or swab)
- DNA extracted in the lab
- PCR amplifies any trichomonas genetic material
- Detection indicates active infection
- Results within a few days
Sample Types
| Sample | For Whom |
|---|---|
| First-catch urine | Men and women |
| Vaginal self-swab | Women — most accurate for women |
| Cervical swab | Women — clinician-collected |
| Urethral swab | Rarely used due to discomfort |
When to Test
- Unusual vaginal discharge with smell
- Itching or irritation
- Pain during sex or urination
- Partner has tested positive
- As part of comprehensive STI screening
Why PCR Is Preferred
- Higher sensitivity than microscopy
- More accurate than culture
- Self-collection works well
- Can be combined with chlamydia and gonorrhoea testing
Window Period
Trichomoniasis can be detected from about 1-2 weeks after exposure. If you test sooner, retest after the window period.
Results
- Positive — active trichomoniasis; treatment needed
- Negative — no detected infection
Treatment
- Metronidazole 400-500mg twice daily for 5-7 days, or single 2g dose
- Avoid alcohol during and 48 hours after treatment
- Partners should be tested and treated
- Avoid sex until both have completed treatment
Where to Test
- NHS sexual health clinics
- Some home test kits include trichomoniasis
- GP surgery
- Private clinics
Why Trichomoniasis Testing Matters
- Up to half of cases are asymptomatic
- Untreated infection can cause complications
- Increases HIV risk
- Easily curable with the right test and treatment
Read more: What is trichomoniasis? | Trichomoniasis testing overview | Trichomonal vaginitis
Frequently Asked Questions
Is PCR testing for trichomoniasis accurate?
Very accurate — gold standard for diagnosis.
Can I test for trichomoniasis at home?
Some home kits include it. Check before ordering.
How is it different from microscopy?
PCR is more sensitive and reliable than visual identification under a microscope.
Related reading
- How Accurate Are Rapid HIV Tests?
- Anonymous STI Testing: What It Means
- Are HIV Tests Accurate If You're on PrEP, PEP or ART?
- Are STI Blood Tests Accurate?
- Before You Get Intimate: Why You Should Ask About STI Testing
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.
