Evaluation of the revised serum calcium procedure used with the Du Pont automatic clinical analyzer.

We evaluated a revised serum calcium method (o-cresolphthalein complexone) used with the Du Pont aca. Our results correlated well with those obtained by atomic absorption spectrometry. Within-run and day-to-day coefficients of variation were 0.5 and 1.5%, respectively. Color produced and calcium concentration are linearly related and the relation is not affected by hemolysis, lipemia, or icterus.