Kahn's test

A simple quantitative precipitation test for syphilis. Used in several modifications. The precipitation agent is an alcoholic extract of bovine heart with cholesterol added. Kahn's test is faster and simpler than the Wassermann test – which required a two-day incubation period – and can be completed in a matter of minutes. However, it can also be inaccurate and show false positive and negative results.

Kahn found that by adjusting the temperature, salt concentration, and serum dilution used in his test, the reaction could indicate the presence of the agents of tuberculosis, malaria, or leprosy in the blood sample. He therefore called it the universal serological reaction.

• R. L. Kahn:
  A simple quantitative precipitation reaction for syphilis.
  Archives of Dermatology and Syphilology, Chicago. 1922, 5: 570-578 and 734-743.
  
• R. L. Kahn:
  Rapid Precipitation Phase of the Kahn Test for Syphilis, with New Method for Indicating Results.
  Journal of the American Medical Association, July 1923, 81: 88-92.
• R. L. Kahn:
  A Simple Quantitative Precipitation Reaction for Syphilis.
  Michigan Department of Health Reprint Series, Lansing, Numbers 9, 10 and 11, January, 1923.
  Number 9: A Simple Quantitative Precipitation Reaction for Syphilis, Preliminary Communication.
  Number 10: A Simple Quantitative Precipitation Reaction for Syphilis, Second Communication.
  Number 11: A Simple Quantitative Precipitation Reaction for Syphilis, Third Communication.
• C. C. Young:
  The Kahn Test for Syphilis in the Public Health Laboratory.
  American Journal of Public Health, February 1923, 13: 96-99.
• R. L. Kahn:
  Serum diagnosis of syphilis by precipitation. Baltimore 1925.
• R. L. Kahn:
  The Kahn Test: a Practical Guide. Baltimore, Williams & Wilkins, 1928.
• R. L. Kahn:
  Über meine Flockungsreaktion bei Syphilis.
  Klinische Wochenschrift, Berlin, 1928, 7: 2014-2017.
• R. L. Kahn, G. Lubin, E. McDermott:
  Studies on antigen for the Kahn test. III. The correction of antigen.
  Journal of Laboratory and Clinical Medicine, St. Louis, 1929, 14: 979-994.
• R. L. Kahn, E. McDermott:
  The Kahn reaction with spinal fluid.
  American Journal of Syphilis, 1929, 13: 557-569.
• R. L. Kahn:
  Technique of the standard Kahn test and of special Kahn procedures.
  University of Michigan, 1944.
• R. L. Kahn:
  An introduction to the Universal Serologic Reaction in Health and Disease.
  The Commonwealth Fund, New York, 1951.