Impact of Time Delay in the Analysis of Serum Ionized Calcium, Sodium, and Potassium

Introduction Delay in the analysis of serum electrolytes along with clot contact time can lead to difference in results significant enough to affect clinical decisions. This study was undertaken to evaluate the effect of time lag between centrifugation and analysis on levels of serum sodium, potassium, and ionized calcium in a tertiary level health care set up. Materials and Methods In this cross-sectional study, 70 serum samples were analyzed for ionized calcium, sodium, and potassium under different conditions with respect to time lag and clot contact time. The analysis of ionized calcium was done on Eschweiler Combiline 2, a direct ion-selective electrode (ISE) analyzer. Serum sodium and potassium were analyzed on fully automated chemistry analyzer, which is an indirect ISE analyzer. The statistical analysis was done in IBM SPSS software version 21. Results The results for intergroup comparison with different time lag and clot contact time between all the four groups for sodium, potassium, and ionized calcium were statistically significant, as obtained by application of Kruskal-Wallis test. There was consistent decrease in the concentration of sodium and ionized calcium, and an increase in serum potassium with increased delay in analysis and clot contact time. Conclusion The accurate measurement of electrolytes is of paramount importance for the treatment and better prognosis of critically ill patients. This can be accomplished by better management of the preanalytical phase of analysis by maintaining a standard protocol in the laboratory and sample transportation.