Kahn test

medicine

Written by

The Information Architects of Encyclopaedia Britannica

Last updated

June 30, 2026

Quick Summary

The Kahn test, developed by immunologist Reuben Leon Kahn, is a medical diagnostic test primarily used for detecting syphilis. It works by mixing an infected blood sample with beef heart muscle serum and cholesterol, which causes clouding if syphilis is present. While known to sometimes produce false-positive results, it was considered more efficient than the slower Wassermann test. Kahn later expanded the test, termed the universal serologic reaction, to indicate the presence of tuberculosis, malaria, or leprosy by adjusting temperature, salt concentration, and serum dilution.1

Summary created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

2 Britannica Sources

Ask Britannica AI about this topic

Britannica doesn't have a full article on this topic, so we've curated a list of our relevant coverage.

Reuben Leon Kahn
…came to be called the Kahn test, has been known to yield false-positive results in persons recently vaccinated or suffering from diseases other than syphilis, it has proved more useful than the slower Wassermann test.
Read More
…came to be called the Kahn test, has been known to yield false-positive results in persons recently vaccinated or suffering from diseases other than syphilis, it has proved more useful than the slower Wassermann test.
Read More