Diagnosis of urogenital gonorrhoea: evaluation of an enzyme immunoassay and use of urine as a non-invasive specimen.

Urethral swabs and urine samples were collected from 42 male patients attending a social hygiene clinic in Hong Kong and used for gonococcal culture and detection of antigens by enzyme immunoassay. Of the patients, 21 were suffering from gonorrhoea as indicated by positive gonococcal culture from both urethral swabs and urine. Twenty of the positive cases were detected by both swab and urine specimens using Gonozyme, an enzyme immunoassay kit. One culture-positive case failed detection by both swab and urine specimens. Gonozyme showed sensitivity and specificity of 95.2% and 100% respectively. With male patients, the use of urine as an alternative specimen to urethral swabs appears to have potential value for both culture and Gonozyme testing. Genital swabs and urine samples were subsequently collected from 108 patients (89 male, 19 female) attending the sexually transmitted disease monitoring centre in Guangzhou, China. Gonozyme tests were performed on both types of specimen, while only swabs were cultivated. When compared with swab culture, Gonozyme had sensitivity and specificity of 100% and 89.2% for males, and 100% and 90.9% for females, respectively. When urine was compared with swabs in the Gonozyme test, urine had sensitivity and specificity of 83.6% and 89.2% for males, and 62.5% and 81.8% for females, respectively. Hence, Gonozyme merits further investigation as an acceptable rapid diagnostic method for detection of Neisseria gonorrhoeae, especially when using urine as an alternative non-invasive specimen from male patients.