Automated determination of anti-streptolysin O antibodies by a kinetic hemolytic method.

An automated method which uses oxidized Streptolysin O and determines the anti-Streptolysin O titer in whole blood without dilution of the sample is described. The addition of a reducing agent starts the hemolysis at an initial rate which is inversely proportional to the anti-Streptolysin O titer of the sample. An instrument (Taso-matic), designed to automatically execute all of the procedures, was used. Comparison between the described method and the classical hemolytic method gave the following linear regression slope y = 1.06x-13 (r = 0.974). Precision of the method at two different anti-Streptolysin O titers (200 and 500 IU), expressed as relative standard deviation, was 12.1 and 4.7% in the between-run procedure and 10.1 and 4.9% in the within-run procedure, respectively.