Determination of C3 nephritic factor activity by a microassay based on the peroxidase-like activity of the heme group.

We report a modification of a method for measuring the C3 nephritic factor, using the peroxidase activity of the heme group. This modification increases the sensitivity of the method, approximately seven-fold when NEF activities are measured in U/mL. It is less time-consuming and it allows the simultaneous testing of a larger number of samples, simplifying the screening of sera and ensuring an easy and simple test for the detection of NEF in purification processes as well as in in vitro production. The method could also be useful in other hemolytic assays.