What are the methods for diagnosing Trichomonas (Trichomonas vaginalis) infection in males?

From the Guidelines

Testing for trichomonas in men should typically involve nucleic acid amplification tests (NAATs) on a urine sample, which is the most sensitive and preferred method, as recommended by the 2018 update by the Infectious Diseases Society of America and the American Society for Microbiology 1.

Key Points to Consider

• First-void urine (the initial portion of the urine stream) provides the best specimen for NAATs.
• Alternative testing methods include urethral swabs or microscopic examination of urethral discharge, though these are less sensitive.
• Men should avoid urinating for at least one hour before providing a urine sample to ensure accurate results.
• Testing is particularly important for men with urethritis symptoms (discharge, burning during urination) or whose sexual partners have been diagnosed with trichomoniasis.

Importance of Testing

• Many men with trichomonas infection are asymptomatic but can still transmit the infection, making testing valuable even without symptoms.
• If positive, treatment consists of a single 2-gram oral dose of metronidazole or tinidazole, as suggested in the context of sexual assault management 1.
• Sexual partners should also be treated simultaneously, and patients should abstain from sexual activity until both they and their partners complete treatment and are symptom-free.

Complications and Risks

• Untreated trichomoniasis can increase the risk of acquiring or transmitting HIV and may cause complications like prostatitis or epididymitis in men.
• The CDC recommends empirical treatment of Chlamydia, gonorrhea, and trichomoniasis in cases of sexual assault, highlighting the importance of testing and treatment in such scenarios 1.

From the Research

Testing for Trichomonas in Men

• Trichomonas vaginalis infection is a common sexually transmitted infection (STI) that can affect both men and women 2, 3.
• In men, Trichomonas vaginalis infection is often asymptomatic, but it can cause non-gonococcal urethritis 3.
• Nucleic acid amplification tests (NAATs) are more sensitive than culture for detecting T. vaginalis in men 2, 4.
• The cobas TV/MG assay is a suitable diagnostic test for detecting T. vaginalis in men, with high sensitivity and specificity 4.
• Factors associated with T. vaginalis infection in men include younger age, African American race, and ≥5 polymorphonuclear cells per high-power field on urethral Gram stain 5.

Diagnosis and Detection

• NAATs can detect T. vaginalis DNA in urogenital specimens from men and women, including urine samples and meatal swabs 4.
• The sensitivity of NAATs for detecting T. vaginalis in men is high, ranging from 94.7% to 100% 4, 5.
• The specificity of NAATs for detecting T. vaginalis in men is also high, ranging from 92.5% to 98.4% 4.
• NAATs can detect approximately one-third more infections among women than wet mount alone 5.

Prevalence and Risk Factors

• The prevalence of T. vaginalis infection is high among men and women attending sexually transmitted diseases clinics, with an overall prevalence of 20.2% 5.
• Correlates of T. vaginalis infection among men include age >40 years, African American race, and ≥5 polymorphonuclear cells per high-power field on urethral Gram stain 5.
• Risk factors for T. vaginalis infection among women include age >40 years, African American race, leukorrhea on wet mount, elevated vaginal pH, positive whiff test, and concurrent gonococcal infection 5.