Evaluation of the limulus amebocyte lysate assay for presumptive diagnosis of gonorrhea in men at a clinic for sexually transmitted diseases.

Specimens of urethral exudate from 200 men with uncomplicated urethritis were tested for Neisseria gonorrhoeae by the limulus amebocyte lysate assay, culture on modified Thayer-Martin medium, and gram-stained smear. As compared with cultures, the sensitivity and specificity of the limulus assay were 94.8% and 89.3%, respectively, while the sensitivity and specificity of the gram stain were 98.8% and 100.0%, respectively. The accuracy of prediction of the presence of N. gonorrhoeae was significantly better by gram-stained smear than by the limulus assay. Unless the limulus assay is modified, as it was in this study, it does not appear to have a role in the presumptive diagnosis of the gonorrhea in men at a clinic for sexually transmitted diseases.