Identification of problem Neisseria gonorrhoeae cultures by standard and experimental tests

Standard and experimental tests were used by a reference diagnostic laboratory to determine the identity of 182 "suspected" Neisseria gonorrhoeae isolates submitted by state health departments because of inconclusive laboratory results. More than 97% of these cultures were subsequently identified by a rapid microcarbohydrate test in conjunction with confirmatory immunological procedures. The experimental rapid slide agglutination test using rough-lipopolysaccharide antibody, the Phadebact co-agglutination test, and fluorescent antibody test identified 49.3 to 94.1% of these cultures. Because of frequent problems with carbohydrate utilization, Neisseria meningitidis and Branhamella catarrhalis were the two microorganisms most often confused with N. gonorrhoeae by submitting laboratories.