Since the Kahn test was first announced five years ago, it has been steadily gaining favor as a laboratory aid in the diagnosis of syphilis. In the beginning, the test was regarded as having only academic interest. Later, workers began to consider it a valuable check on the Wassermann test. Still later, especially with greater mastery of technic, many workers began to find the Kahn test the more dependable of the two methods. The result has been that during the past several years the Kahn test has replaced the Wassermann test in a number of laboratories. In this article, an attempt will be made to discuss briefly some of the practical features of the Kahn test, the relationship between the Wassermann and the Kahn test, and the interpretation of the latter.
It is twenty years since the first attempt was made, by Michaelis, to evolve a precipitation method for detecting