Rapidity and reliability of gonococcal identification by coagglutination after culture on modified New York City medium.

The combination of culture on modified New York City (MNYC) medium and identification of neisserial isolates by the Phadebact gonococcus test was evaluated in routine laboratory practice. The sensitivity of coagglutination was 96.7% (318/329 isolates) and that of immunofluorescence (IF) 97.9% (322/329 isolates); the specificity of both methods was 96.8% (120/124 isolates). Of the 329 gonococcal isolates, 286 (86.9%) could be tested by coagglutination and 309 (93.9%) by IF after only 24 hours' incubation. Identification by coagglutination from primary cultures on MNYC medium is considered to be very rapid, simple, and efficient for the cultural diagnosis of anogenital gonorrhoea in women and urethral gonorrhoea in men. Because of the high prevalence of meningococci in the pharynx and their not infrequent occurrence in the anorectum of homosexual men the identity of isolates from these sites is best confirmed by sugar utilisation tests.