Diagnosis of urethritis

Diagnosis of urethritis is supported by clinical symptoms (dysuria, urethral irritation, or meatal pruritus) and/or presence of a visible discharge or presence of balano-posthitis (1).

The diagnosis of urethritis should be confirmed by

• microscopy of either a urethral swab or first-void urine sample
  • a Gram stained urethral smear containing >=5 polymorphonuclear (PMNL) per highpower (x1000) microscopic field (averaged over five fields with greatest concentration of PMNLs)
    • either a 5-mm plastic loop or cotton tipped swab can be used which should be introduced about 1cm into the urethra
      • a 5-mm plastic loop is less painful than a Dacron swab which is less painful than a Rayon swab
    • if a urethral discharge is present and can be adequately sampled without placing the loop or swab inside the meatus, then this is the recommended method for obtaining a smear as it is likely to be preferred by the patient
  • a Gram stained preparation from a centrifuged sample of a first passed urine (FPU) specimen, containing >=10 PMNL per highpower (x1000) microscopic field (averaged over five fields with greatest concentration of PMNLs) (1)

All patients with should be tested both for Chlamydia and Gonorrhoea. If available, testing male patients with urethritis for M. genitalium should be performed (1,2)

• Chlamydia trachomatis - nucleic acid amplification test (NAAT)
• Gonorrhoea - urethral smear microscopy, NAAT and culture (2).

In case of suspected UTI (e.g. - severe dysuria, haematuria (microscopic or macroscopic), nocturia, urinary frequency, urgency) or if the patient is at low risk for a sexually transmitted infection, a urinary dipstick analysis on a mid-stream urine (MSU) specimen should be considered and a MSU sample should be sent for culture and sensitivity (2).

Note:

• first-void urine is the specimen of choice for NAATs (2)

Reference:

1. Horner P et al. 2015 UK National Guideline on the management of non-gonococcal urethritis. Int J STD AIDS. 2016;27(2):85-96.
2. Moi H, Blee K, Horner PJ. Management of non-gonococcal urethritis. BMC Infectious Diseases. 2015;15:294.