Sero-diagnosis of gonorrhoea with a microprecipitin test using a lipopolysaccharide antigen from N. gonorrhoeae.

Serum tests for gonorrhoea, particularly the complement-fixation procedure using whole gonococcal cells as the antigen, have long been recognized to be of very limited value in diagnosis. For more efficient diagnosis and control of gonorrhoea there is clearly a need for a simple serological method which can be used as a screening test aimed particularly at the detection of the female carrier in circumstances in which discretion is required and in which routine genital examination is not practicable. In this context a simple "microprecipitin ring test", using a specific lipopolysaccharide antigen of gonococcal origin, has been devised. Preliminary trials have shown its possible usefulness (Chacko and Nair 1966a). The present report gives the results of a more extensive evaluation. The kinetics of the precipitin ring test were described by Nair and Chacko (1966).