The precipitation method proposed in this paper is based on the employment of syphilitic serum with alcoholic extract antigens of heart muscle. In this regard it is similar to the precipitation reactions of Meinicke,1 Sachs and Georgi2 and Dreyer and Ward (sigma reaction).3 The test proposed, however, differs from each of these reactions in essential phases. Among these are the preparation of the antigens and their proper dilution for the tests, as well as the concentration of serum and antigen in the tests. As a result of these and other technical factors, the test possesses the following salient features:
The diluted antigen possesses considerable stability. This dispenses with the necessity of diluting fresh antigen with salt solution before using it in the tests.
The strongly positive serums show, in most cases, spontaneous precipitation, and the test as a whole is completed after three hours' incubation
KAHN RL. A SIMPLE QUANTITATIVE PRECIPITATION REACTION FOR SYPHILIS: PRELIMINARY COMMUNICATION. Arch Derm Syphilol. 1922;5(5):570–578. doi:10.1001/archderm.1922.02350300011003
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