Can Serum Replace Plasma for Glucose Estimation? – An Integrity Check

Glucose is the most common parameter to be estimated in a clinical laboratory. However, being highly unstable, the reported values often lead to under diagnosis of diabetes mellitus. This exerts a greater pressure on the laboratories as this reflects their quality. The aim of the study was to analyse the stability of the parameter in serum and plasma samples in a time delay of 1 hour and 2 hours in a tertiary care laboratory in South-India. The study included 125 samples of serum and plasma. Glucose was estimated by Hexokinase method. The serum and plasma samples were separated following the standard operating procedures of the laboratory. They were grouped as A and B. The samples of Group A and B were estimated for glucose concentration at 0, 1 and 2 hours and the values were noted against the time. The serum samples were stored at 2-4 degrees Celsius in between the estimations at 1 and 2 hours. The glucose concentration at 0, 1 and 2 hours were compared to each other with the help of Analysis of variance (ANOVA). The significance p of the ANOVA test performed to compare serum glucose concentrations analyzed at 0, 1 and 2 hours was found to be 1.000, with a p-value of 0.999 for the plasma sample glucose concentrations. It was evident that glucose concentration was stable with the p value closer to 1.000 in plasma samples estimated at 0, 1 and 2 hours. Plasma can be replaced with serum during the first hour without much alterations in the glucose concentration when stored at 2-4 degrees Celsius. 