Abstract
Aim: This study aimed to evaluate the long-term stability of cattle plasma and serum, measuring changes in the concentration of some biochemical analytes under different temperatures and time conditions of storage, and assessing the potential clinical impact of these changes.
Methods: A total of 7 biochemical analytes in the serum and plasma of seventy-four adult cattle were examined following storage. After determining the baseline measurements (D0), the serum and plasma of each cattle were aliquoted and stored at 4°C and −20°C for 15, 45, 75, 105, 135, 165, and 180 days and then analyzed for stability. The results were compared with the initial analysis measurements obtained from fresh samples. The mean concentrations of biochemical analytes in different storage conditions were compared to the initial concentrations (D0) using a paired t-test and compared to reference values to evaluate the potential clinical impact.
Results: The glucose, creatinine, and cholesterol were stable under all conditions. Glucose and aspartate aminotransferase (AST) concentration in serum vs. plasma did show significant differences (p<0.05). Uric acid had a clinically significant loss of stability under all conditions (p<0.05). The instability for total bilirubin at D180 was stored at 4°C and -20°C (p<0.05) in serum and plasma, but the potential clinical impact was statistically significant in only serum samples. The instability for total protein at D45, D135, D165, D180, and D15, D75, D105, D135, D180 stored at 4°C and -20°C (p<0.05) in the serum samples, respectively. The potential clinical impact was observed at D165 to D180 store at 4°C and D180 store at -20°C in the serum sample. The means of AST was a significant (p<0.05) variation in storage at D180 in (-20°C) serum samples without clinical impact and at D165 & D180 in (4°C) plasma samples with clinical impact.
Conclusion: Serum samples were comparatively better than plasma samples for most biochemical analytes. Storing samples at -20°C is a better way to preserve total bilirubin, total protein, and AST. Therefore, the samples had to be kept in separate aliquots for re-analysis as the stability of the analytes decreased if thrown and stored again. However, this study will provide reference results for interpreting clinical diagnostic reports and determining the temperature and time length for storing laboratory samples.