An indirect haemagglutination test for demonstration of gonococcal antibodies using gonococcal pili as antigen. I. Methodology and preliminary results.

An indirect haemagglutination (IHA) test for detection of gonococcal antibodies in human sera was established using purified pili as antigen. The majority of sera (44/51), positive in the gonococcal complement fixation test, were also positive in the IHA test with titres within the range 320-10,000. The results obtained for the following three groups of sera indicate a comparatively high speicificity of the IHA test; 1) 52 sera from children below 12 years of age were all negative, 2) 98% (184/188) of sera from blood donors were negative, 3) only sera from three adults out of 21 patients with meningococcal infections gave a positive reaction.