“…However, false-negative results with direct fluorescent-antibody (DFA) (1,8,13,22,23) and coagglutination (3,11,12,20) have been reported. Gonococci can rapidly produce changes in their outer membrane protein (the target for monoclonal antibody tests; 5,10,13,14,20,25), resulting in false-negative DFA or coagglutination results (1,13,17). False-positive results have been reported less frequently with these reagents, although one false-positive result with GonoGen for an isolate of N. meningitidis has been reported (3).…”