Diagnosis of gonorrhea using a genetic transformation test on mailed clinical specimens

The genetic transformation test (GTT), a technique used for the detection of gonococcal DNA in clinical specimens, was compared with culture testing for the diagnosis of gonorrhea. At the De Kalb County Venereal Disease Clinic, Decatur, Ga., 454 cervical and 160 rectal specimens from women and 191 urethral specimens from men were collected in duplicate. One of each of the two specimens from each anatomic site was immediately plated on Martin-Lewis medium and incubated; the other specimen was mailed to Philadelphia for a GTT. Using culture results as a standard, the GTT had a specificity of 98.1% although some "false-positive" GTT results were probably a reflection of false-negative culture results. The sensitivity of the GTT was greater than 96% except when specimens were collected with Culturettes (Marion Laboratories, Kansas City, Mo.). In situations where Gram staining is not appropriate or where on-site culture facilities are not available, GTT may be the method of choice for the diagnosis of gonorrhea.