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Nongonococcal Urethritis (NGU)
1996 Case Definition

Clinical Description

Urethral inflammation that is not the result of infection with Neisseria gonorrhoeae. Urethral inflammation may be diagnosed by the presence of one of the following criteria:

  • A visible abnormal urethral discharge, OR
  • A positive leukocyte esterase test from a male aged less than 60 years who does not have a history of kidney disease or bladder infection, prostate enlargement, urogenital anatomic anomaly, or recent urinary tract instrumentation, OR
  • Microscopic evidence of urethritis (greater than or equal to 5 white blood cells per high-power field) on a Gram stain of a urethral smear

Laboratory Criteria for Diagnosis

No evidence of N. gonorrhoeae infection by culture, Gram stain, or antigen or nucleic acid detection

Case Classification


A clinically compatible case in a male in whom gonorrhea is not found, either by culture, Gram stain, or antigen or nucleic acid detection


Nongonococcal urethritis is a clinical diagnosis of exclusion. The syndrome may result from infection with any of several agents (see Chlamydia trachomatis, Genital Infection). If gonorrhea and chlamydia are excluded, a clinically compatible illness should be classified as NGU. An illness in a male that meets the case definition of NGU and C. trachomatis infection should be classified as chlamydia.