Tricomoniasis Diagnosis and Considerations

Clinical Presentation

The Centers for Disease Control and Prevention recommends considering tricomoniasis in any woman with vaginal discharge, especially when the vaginal pH is >4.5, and in all patients with risk factors for sexually transmitted infections, regardless of symptoms 1, 2
Women with symptomatic tricomoniasis may present with vaginal discharge with or without a characteristic odor 2
Pruritus or vulvar irritation is also a common symptom in women with tricomoniasis 2
A high vaginal pH (>4.5) is a key finding that distinguishes tricomoniasis from candidiasis 1, 2, 3
The "strawberry cervix" (punctate red lesions on the cervix) is a specific but not always present finding in tricomoniasis 3, 4
Friability and cervical hyperemia may also be present in women with tricomoniasis 3

Up to 50% of tricomoniasis infections are asymptomatic, so the absence of symptoms does not exclude infection 5
The Centers for Disease Control and Prevention recommends screening for tricomoniasis in asymptomatic women with multiple sexual partners 5

The American Academy of Pediatrics recommends using a wet mount examination to diagnose tricomoniasis, but notes that the sensitivity is only 40-80% 1, 6
The wet mount examination requires living organisms and must be performed within 30 minutes to 2 hours of collection 1, 6
If the wet mount is negative but clinical suspicion is high, more sensitive tests such as NAAT, culture, or rapid antigen tests should be used 1, 3, 6
The Centers for Disease Control and Prevention recommends evaluating vaginal pH and performing a wet mount examination immediately if a microscope is available 1, 3

The Centers for Disease Control and Prevention recommends screening for tricomoniasis in high-risk asymptomatic populations using NAAT, which is more sensitive than wet mount 6
The American Academy of Pediatrics recommends always evaluating and treating sexual partners simultaneously to prevent reinfection 7

Nucleic acid amplification testing (NAAT) is the most appropriate diagnostic test for trichomoniasis, offering superior sensitivity compared to all other methods and accepting multiple specimen types including vaginal swabs, endocervical swabs, urine, and liquid-based cytology specimens 8, 9
The Centers for Disease Control and Prevention recommends NAAT as the preferred diagnostic method when available, as it provides the highest sensitivity and does not require viable organisms for detection 8, 9
Multiple specimen types can be used for NAAT: vaginal swabs, endocervical swabs, urine, liquid-based cytology specimens, and even urethral, rectal, or pharyngeal swabs 8, 9
Specimens remain stable at room temperature for 7 days (or per manufacturer's recommendations), allowing flexibility in transport 8, 9
The FDA has cleared NAAT testing (such as APTIMA Trichomonas vaginalis test) for both screening and diagnosis in women 8, 10

The InPouch TV culture system allows both immediate smear review by wet mount and subsequent culture, with a sensitivity of approximately 70% compared to NAAT methods 8, 11, 10
Culture is not widely available and has been largely superseded by NAAT 8, 11
The Affirm VP III Assay detects Trichomonas vaginalis but has lower sensitivity than NAAT 8, 11, 10
The OSOM Trichomonas Rapid Test is one commercially available option for rapid antigen testing, with a sensitivity ranging from 62% to 95% compared to culture and NAAT 8, 11, 10

Never rely solely on wet mount due to its poor sensitivity of 40-80%; negative wet mount does not exclude trichomoniasis 8, 11
Do not delay wet mount examination beyond 2 hours, as organisms lose motility and become undetectable 8, 9