Comparison of Thayer-Martin, Transgrow, and Gonozyme for detection of Neisseria gonorrhoeae in a low-risk population.

The Gonozyme test (Abbott Laboratories, North Chicago, IL) an enzyme-linked immunosorbent assay procedure, on-site Thayer-Martin cultures, and Transgrow cultures were compared for sensitivity and specificity in detecting gonorrhea. For these comparisons triplicate genital swab specimens were obtained from women for the diagnosis of infection with Neisseria gonorrhoeae. Both the Transgrow and the Gonozyme specimens were mailed to a public health laboratory. The population under study was considered to be low-risk. When sensitivity and specificity were calculated on the basis of results of Thayer-Martin cultures, Transgrow had a sensitivity of 57% and a specificity of 100%. Gonozyme had a sensitivity of 80% and a specificity of 99%. In a low-risk population, the predictive value of a positive Transgrow culture was 100%, whereas the predictive value of a positive Gonozyme test was 57%. The predictive value of a negative Transgrow result was 99.7%, and that of a negative Gonozyme test was 99.8%. It is concluded that the use of the Gonozyme procedure for screening of low-risk populations needs further evaluation.