The Worth of Ionized Calcium Levels Calculated by Zeisler, Butler and Hanna Methods in Diagnosis of Hypocalcemia

Abstract

Introduction: It was aimed to examine the diagnostic performance of the ionized calcium levels calculated by the Zeisler, Butler and Hanna method on the evaluation of hypocalcemia. Materials and Methods: Whole blood ionized calcium and serum total calcium levels of 500 individuals aged between 20-60 years were retrospectively screened. Individuals were divided into hypoalbuminemia and normoalbuminemia groups according to their serum albumin concentrations. In these groups, the diagnostic performance of total calcium and ionized calcium concentrations calculated by Zeisler,Butler and Hanna methods in terms of hypocalcemia were examined. While determining hypocalcemia, ionized calcium level was accepted as a reference.The difference and correlation between directly measured ionized calcium and calculated ionized calcium were analyzed by Wilcoxon signed ranks and Spearman correlation analysis. Results: The ionized calcium levels calculated by the Zeisler,Butler, Hanna methods were higher than the directly measured ionized calcium level. The method with the highest sensitivity and accuracy in terms of hypocalcemia was the Zeisler method.However, the specificity and negative predictive values were low.There was no correlation between directly measured ionized calcium and calculated ionized calcium levels in the hypoalbuminemia group. A significant correlation was observed between ionized calcium and calcium levels calculated by the Zeisler and Hanna methods in the normoalbuminemia group,but this correlation was low. No correlation was observed between ionized calcium and calcium calculated by Butler's method. Conclusion : The results of the study limit the use of the Zeisler,Butler and Hanna methods in estimating ionized calcium. We believe that it would not be reliable to comment on the level of ionized calcium with these methods.