Syphilis Test

Syphilis Test

Once a ravaging disease that rose to epidemic proportions, syphilis is effectively treated today with penicillin and other antibiotics. Because there is no known inoculation, accurate testing has become a key determinant of quick and successful treatment.

In 1903, Russian biologist Elie Metchnikoff (1845-1916) and French scientist Pierre-Paul-Emile Roux demonstrated that syphilis could be transmitted to monkeys and, consequently, could be studied in the laboratory. Two years later, German zoologist Fritz Schaudinn and his assistant Erich Hoffmann isolated the bacterium that causes syphilis, a spiral-shaped spirochete called Treponema pallidum.

The first effective test for syphilis was developed in 1906 by German physician and bacteriologist August von Wassermann (1866-1925). Wassermann was influenced by the work of German researcher Paul Ehrlich (1854-1915), who established basic theories of blood immunity. Wassermann's test consisted of taking a blood sample from the patient, and testing it for the antibody to the syphilis bacterium. If antibodies were present, the test was positive. After treatment, if the antibodies disappeared, the test was negative. The Wassermann test was useful in diagnosing syphilis in 95% of cases.

Unfortunately, the Wassermann test required a two-day incubation period. Reuben Leon Kahn (1887-1979), a Russian-born American immunologist, developed a new syphilis test in 1923 that was faster and simpler. This modified test used an extract from beef heart to detect syphilis antibodies. More sensitive than the Wassermann test, the Kahn test could be completed in a matter of minutes. However, the test could be inaccurate, showing false positive or false negative reports. For many years, Kahn studied the reaction of the test animals' immune systems. His research focused on tissue immunity and he found this could vary with the age of the animal, growing stronger with maturity. Kahn conducted his research at the University of Michigan and Howard University.

Another effective syphilis test was developed by William A. Hinton (1883-1959), an African-American physician who became a leading expert on venereal disease. Hinton, who worked out of Harvard Medical School, also collaborated with J. A. V. Davies on the Davies-Hinton test. Several other syphilis tests have been developed. The VDRL test, which came out of the Venereal Disease Research Laboratory, is performed on either cerebrospinal fluid or blood; however, this test produces false negative results about one-third of the time. The rapid plasma reagin (RPR) test is very sensitive but false positives are common, especially in anyone with a rheumatologic disorder. All positive results should be confirmed with one of the treponemal- specific tests such as the fluorescent treponema antibody absorption test (FTA-ABS).

Because syphilis still occurs in epidemic proportions in developing countries and parts of the United States, a quick, low-cost, easy-to-read, and accurate "IC strip test" has been developed by Omega Diagnostics in the United Kingdom with funding from USAID, the World Bank, and others. In 1998, field trials to validate effectiveness of the strip were being planned.