[Consumption hypocomplementemia: relation between hemolytic and immunochemical assays of C4 in serum (author's transl)].

The aim of the study is to compare two methods for the measurement of the fourth human complement component through its hemolytic activity and immunodiffusion properties in 35 healthy subjects and 35 patients with immunological complement depletion. For the healthy subjects, the results show a highly significant correlation between the two methods (the coefficient of correlation is + 0.80). On the contrary, there is no correlation between the two assays for the patients suffering from consumption hypocomplementemia. The reasons of this discrepancy are discussed.