I. Diagnostic points A history of unclean sexual intercourse or spousal infection, symptoms of UTI or cervicitis occurring 1-3 weeks after infection, gonococcal microscopy and culture are negative, urethral discharge smear with multinucleated leukocytes ≥ 5 per field (1000×) is positive, urine sediment examination with multinucleated leukocytes ≥ 15 per field (400×) has diagnostic significance. If possible, serum examination and culture should be done to further confirm the diagnosis. Differential diagnosis (a) gonorrhea The incubation period of gonorrhea is short, averaging 3-5 days; the symptoms of urethritis are obvious, and the urethral discharge is purulent; gram-negative gonococci can be detected. The incubation period of non-gonococcal urethritis is longer; the symptoms of urethritis are mild or absent, and the urethral discharge is scanty and thin mucus-like; no gonococcus can be detected. (ii) Non-specific urethritis Urethritis caused by purulent bacteria such as Staphylococcus and Escherichia coli, often by the spread of inflammation of the genitourinary system or adjacent organs and secondary infections caused by making catheterization and urethral swabs, etc. It is not related to sexual contact. Based on the medical history, it is easy to identify.