Reports that have heretofore appeared on the Kahn test have dealt for the most part with comparisons with the Wassermann test. It seems obvious that the true value of any test may be best established by a comparison with the clinical observations. An opportunity was afforded in this clinic to check the results of the Kahn test against clinical observations, the latter test having recently become standard in the laboratories of the University Hospital.
This study is based on 2,070 blood Kahn examinations. The blood was obtained from patients falling into three groups: those presenting themselves to the clinic for advice regarding various dermatologic conditions; those in whom a diagnosis of syphilis was made or entertained, and those who had received antisyphilitic therapy either in this clinic or elsewhere. Some patients in the syphilitic group came originally to the Dermatology Clinic, and some were referred to the clinic because of