Study of the Stability of Various Biochemical Analytes in Samples Stored at Different Predefined Storage Conditions at an Accredited Laboratory of India

BACKGROUND: Storage of serum and other blood products is often necessary in laboratories because of technical issues or to preserve samples for subsequent research purposes. The aim of this study was to determine whether the stability of biochemical analytes is affected by storage conditions. MATERIALS AND METHODS: A total of 17 biochemical analytes in the sera of ten patients were examined following storage. Subsequent to determining the baseline measurements, the serum of each patient was aliquoted and stored at −20°C for 7, 15, and 30 days and then analyzed for stability. The results were compared with the initial analysis measurements obtained from fresh samples. Mean changes compared to baseline (T0) concentrations were evaluated both statistically and clinically. RESULTS: Our results show that sodium, potassium, urea, creatinine, uric acid, total calcium, phosphorus, direct bilirubin, total bilirubin, aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, total protein, albumin, cholesterol, and triglyceride levels were stable under all conditions. Serum amylase was the only analyte demonstrating instability following prolonged storage; amylase levels changed significantly (both statistically and clinically) at 7, 15, and 30 days (P < 0.05). CONCLUSION: Most common biochemical analytes, except for amylase, showed adequate stability in serum following 30 days of storage at −20­C. Serum amylase analysis should be conducted on the same day that the sample is received in the laboratory.