The first report on the Kahn precipitation test appeared early in 1922.1 By July of that year, more than 15,000 comparative Wassermann and Kahn tests had been completed in the laboratories of the Michigan Department of Health. The observations indicated that to report both tests to Michigan physicians would give them more dependable results than the Wassermann test alone. Accordingly, July 1, 1922, the Michigan Department of Health began to report the Kahn test in addition to the Wassermann on all blood specimens received in the laboratories for the serum diagnosis of syphilis.2
By the latter part of 1923, the Kahn test had become improved and standardized.3 The necessity for incubation had been eliminated, making it possible to read the results of the test within a few minutes after mixing serum with antigen. The preparation and standardization of antigen had been rendered quantitative, assuring a high degree