Study of the Stability of various Biochemical Analytes in Pooled Sera preserved at 4-8 o C

Abstract

Biochemical laboratory plays an important role in today’s clinical practice. The reliability of laboratory results is therefore most important. Through the quality control (QC), errors can be minimized and the laboratory can ensure about the reliability of its results. The quality control sera are useful for this purpose. But commercially available quality control sera are costly and not available at all places. Also at peripheral levels the storage of the sera at very low temperature is not possible. So we have studied the stability of various biochemical analytes in the pooled sera stored in readily available refrigerator. We have collected 42.5 ml of pooled sera in a plastic jar and we have added 7.5 ml of ethanediol to it (15%). This pooled serum is tested for HIV and HBS Ag. Then serum is kept in the refrigerator at 4 – 8 oC . Daily 1-2 ml of the serum is taken in a plastic test tube with new micro pipette tip from the jar after thorough mixing. When serum attains the room temperature various tests were performed. The results of the tests were noted. We have compared these results with ERBA multi-calibrated sera We have studied 10 such pooled sera. We have found that total proteins and bilirubin get deteriorated (values varies more than 10%) early i.e. between 18-20 days in all 10 samples. Then alkaline phosphatase and amylase get deteriorated between 22-26 days. Glucose and albumin remain stable for 27-30 days. Cholesterol, triglycerides and uric acid starts deteriorating after 32 days. SGOT, SGPT, LDH deteriorates after 35 days. Urea, creatinine, calcium and phosphorus remain stable for long period i.e. more than 45 days.