[Optimization of a method for determination of complement activity from 50% hemolysis of sensibilized red blood cells].

The method for determination of compliment activity from 50% hemolysis of sensitized blood cells (CH5) was modified in accordance with the recommendations of the International Clinical Chemistry Association, which could reduce the consumption of reagents, enhance the accuracy and reproducibility of results. The activity of CH50 was calculated for each serum sample by regression analysis, by graphically reflecting the results and by assessing the quality of each performance. The sigma-deviation method was used to calculate the normal CH50 ranges (55-160 conventional units) whose values were in compliance with the international standards. A series of experiments were made to assess the reproducibility of results. To evaluate the diagnostic informative value, the authors analyzed serum samples from 119 persons: 49 apparently healthy individuals, 74 patients with allergic diseases that are generally unattended by hypocomplementemia (Group 1) and 76 with disease the risk of which is increased in the presence of complement system defect (Group 2). Group 1 patients were those who had bronchial asthma or utricaria; Group 2 patients were those who had systemic lupus erythematosus, scleroderma, rheumatoid arthritis, chronic glomerulonephritis, acute glomerulonephritis, chronic furunculosis, chronic tonsillitis, or necrotic vasculitis. In Group 1, the value of CH50 was similar to that in the group of donors (108.0 +/- 3.1 and 105.1 +/- 3.8, respectively; p = 0.565), but it significantly differed from its mean value (91.6 +/- 5.1) in Group 2 (p = 0.00724). The difference in CH50 was also significant in the group of donors and Group 2 (p = 0.0349).