What are the guidelines for using urethral swabs for Nucleic Acid Amplification Tests (NAAT) in male patients suspected of having Trichomonas infection?

Guidelines Supporting Urethral Swabs for NAAT Testing in Men

Primary Guideline Support

The 2018 Infectious Diseases Society of America (IDSA) and American Society for Microbiology (ASM) guidelines explicitly list urethral swabs as valid specimens for NAAT testing in men for multiple sexually transmitted infections. 1

Specific Pathogen Guidelines

Trichomonas vaginalis

• The IDSA/ASM 2018 guidelines specifically include urethral swabs as an optimum specimen type for Trichomonas vaginalis NAAT testing, alongside vaginal, endocervical, urine, rectal, and pharyngeal swabs 1
• The guidelines note that multiple specimen types can be used for sexually transmitted infections including TV, and that testing for males has been validated by some laboratories, though providers should verify availability with their specific laboratory 1
• The Centers for Disease Control and Prevention (CDC) recommends urethral swab specimens for InPouch TV culture system with direct inoculation at bedside when NAAT is unavailable 2

Chlamydia trachomatis

• The IDSA/ASM 2018 guidelines list urethral swabs as acceptable specimens for C. trachomatis NAAT, along with endocervical, vaginal, rectal, pharyngeal, and conjunctival specimens 1
• Pharynx and rectal specimens in men who have sex with men require laboratory validation for those specimen types 1

Neisseria gonorrhoeae

• The 2006 CDC Sexually Transmitted Diseases Treatment Guidelines state that NAATs are FDA-cleared for use with male urethral swabs for gonorrhea detection 1
• The guidelines emphasize that NAATs offer the widest range of testing specimen types, including male urethral swabs, with high specificity (>99%) and sensitivity (>95%) 1
• Culture and nucleic acid hybridization tests specifically require male urethral swab specimens 1

Important Caveats and Limitations

FDA Clearance Considerations

• Product inserts for each NAAT vendor must be carefully examined to assess current indications, as FDA-cleared specimen types may vary between manufacturers 1
• Some tests are FDA-cleared for both screening and diagnosis in women but may have different clearances for male specimens 1

Laboratory Validation Requirements

• Testing for males and alternate sites has been validated by some laboratories, but providers must verify availability with their specific laboratory before ordering 1
• Some noncommercial laboratories have initiated NAAT of urethral specimens after establishing performance to meet CLIA requirements 1

Specimen Collection Technique

• The 2010 Eastern European Sexual and Reproductive Health Network guidelines provide specific collection instructions: clean the external urethral opening with saline-moistened swab, draw back prepuce to avoid contamination, and insert cotton-wool or Dacron swab carefully into the external urethral meatus to a depth of 0.5-2 cm 1

Clinical Context

• Urethral swabs are particularly valuable for symptomatic men with urethral discharge or urethritis symptoms, as well as asymptomatic men whose female partners are diagnosed with trichomoniasis 2
• Up to 80% of male trichomoniasis infections are asymptomatic, making specimen collection critical even without symptoms 2
• For gonorrhea, when urethral discharge is present, a meatal specimen is an adequate substitute for an intraurethral swab 3