Kahn has recently published a highly sensitive method with spinal fluids for detecting neurosyphilitic involvement, known as the presumptive procedure.1 A similar method with serum has already been in use for several years supplementary to the regular Kahn test with serum, which is conservative in sensitiveness.2 Many reports have appeared in the literature on the regular test with spinal fluid, the consensus being that this test is specific for neurosyphilis but is conservative in sensitiveness.3 A highly sensitive method with spinal fluids would be of great value to clinicians, since it might detect invasion of the central nervous system by Spirochaeta pallida before the appearance of clinical symptoms. In this article, I shall discuss the relative increase in sensitiveness of the presumptive procedure over the regular Kahn test with spinal fluids.
In July, 1928, the Kahn test was made standard in the serologic laboratory of the University
McDERMOTT EB. THE KAHN PRESUMPTIVE PROCEDURE WITH SPINAL FLUIDS. Arch NeurPsych. 1930;23(3):531–535. doi:10.1001/archneurpsyc.1930.02220090122009