A simplified ELISA method for syphilis.

A new serological method for syphilis using a modified ELISA reaction is given. The reaction is performed on polystyrene carriers which have absorbed an ultrasonicated preparation of T. pallidum. The reaction between the antigen and antibody is detected by means of the addition of antihuman IgG swine globulin conjugated with horseradish peroxidase. To make the reaction visible, addition of 5-methyl-9-aminocarbazol in dimethylformamide is necessary. In a positive case of syphilis the carrier becomes a red-brown-violet color; in a negative reaction the white color does not change. The results obtained with this reaction are in absolute concordance with those of FTA-ABS and TPHA.