Immunological identification of Neisseria gonorrhoeae with monoclonal and polyclonal antibody coagglutination reagents.

The reliability of immunological identification of Neisseria gonorrhoeae using polyclonal and monoclonal antibody coagglutination reagents has been evaluated. When clinical isolates of neisseriae were tested in an "in use" trial the sensitivity and specificity of each reagent were similar and the overall agreement with carbohydrate utilisation was 97.9% (141/144) for the polyclonal antibody reagent and 97.2% (140/144) for the monoclonal reagent. When results of testing 13 stock cultures of N lactamica and five stock cultures of beta-lactamase producing Branhamella catarrhalis were combined with the results for clinical isolates of non-gonococcal neisseriae the agreement with carbohydrate utilisation was 86.5% (64/74) for the polyclonal reagent and 97.3% (72/74) for the monoclonal reagent: this difference is statistically significant at the 5% level. Calculation of positive and negative predictive values showed differences in the reliability of the coagglutination reagents when testing Gram negative diplococci isolated from various anatomical sites. The value and limitations of the polyclonal and monoclonal reagents were similar with respect to anogenital isolates: N gonorrhoeae was confirmed by a positive result but not excluded by a negative result. The monoclonal reagent was superior for testing throat isolates; although a negative result with either reagent confirmed Gram negative diplococci as non-gonococcal neisseriae, a positive result with the monoclonal reagent was more reliable (predictive value 93%) than a positive result with the polyclonal reagent (predictive value 86%).