From the Guidelines
For diagnosing male urethral discharge, a nucleic acid amplification test (NAAT) on a urethral swab or urine specimen is recommended due to its high sensitivity and specificity. The swab should be gently inserted 2-4 cm into the anterior urethra after the patient has not urinated for at least one hour to ensure adequate specimen collection. Before obtaining the sample, the urethral meatus should be cleaned to avoid contamination. If discharge is visible, it can be directly collected; if not, urethral stripping (gently massaging the urethra from the base of the penis toward the meatus) may help express discharge.
- The collected specimen should be immediately placed on appropriate culture media or in transport medium, or prepared for microscopic examination.
- This technique allows for detection of common urethritis pathogens such as Neisseria gonorrhoeae and Chlamydia trachomatis.
- Proper specimen collection is crucial as inadequate sampling can lead to false-negative results and delayed treatment, as noted in studies such as 1 and 1.
- It's also important to consider that NAATs are now preferred for these specimens due to their high sensitivity and specificity, as stated in 1 and 1.
- A Gram stain of a male urethral specimen can be considered diagnostic for infection with N. gonorrhoeae in symptomatic men, but a negative Gram stain should not be considered sufficient for ruling out infection in asymptomatic men, as mentioned in 1.
From the Research
Types of Swabs for Male Urethral Discharge
- Urethral swabs are the samples of choice for point-of-care Gram stain testing to diagnose Neisseria gonorrhoeae infection and nongonococcal urethritis (NGU) in men 2.
- Meatal swabs have been recommended as an alternative to urethral swabs for the collection of urethral discharge to diagnose N. gonorrhoeae and Chlamydia trachomatis infection in certain populations by nucleic acid amplification testing (NAAT) 2.
- However, meatal swabs may not be suitable for Gram stain testing in the absence of visible discharge, as they are associated with a significant reduction in cellular content and a higher failure rate of Gram stain smears compared to urethral swabs 2.
Recommendations for Swab Selection
- If Gram stain testing is being considered for point-of-care diagnosis of N. gonorrhoeae infection or NGU in men, urethral swabs are recommended 2.
- Meatal swabs may be used as an alternative to urethral swabs for NAAT, but their use should be limited to cases where visible discharge is present 2.
- The choice of swab type should be based on the specific diagnostic test being used and the presence or absence of visible discharge 2.
Diagnostic Considerations
- Urethral discharge is a common presentation of sexually transmitted infection (STI) in men, and known pathogens include Neisseria gonorrhoeae and Chlamydia trachomatis 3, 4, 5.
- A diagnosis of urethritis can be made based on symptoms, laboratory tests, and physical examination findings 5, 6.
- The goals of treatment include alleviating symptoms, preventing complications, and reducing the transmission of coinfections 5.