Threshold Time to Onset Serum Biochemical Changes of Turkoman Racehorses at Different Serum-Clot Contact Times and Temperatures

BACKGROUND: It is essential to minimize the effect of time and temperature on the serum biochemical parameters and determine the stability limits of each analyte in pre-centrifuged blood samples. OBJECTIVES: This study aimed to investigate the stability limits of 10 analytes in Turkoman racehorses blood samples stored in different temperatures and time points. METHODS: The whole blood samples from healthy horses (n=10) were stored for 2 h (baseline), 6, 12, 24, and 48 h at 25ºC or 4ºC. The commercial kits (Parsazmoon, Tehran, Iran) were used for the samples analysis. RESULTS: Albumin (ALB), total bilirubin (TB), and phosphorous (P) exhibited remarkable changes at 25ºC. The storage time for as long as 12 h at 25ºC had no significant effect on urea, total protein (TP), lactate dehydrogenase (LDH), creatinine, and alkaline phosphatase (ALP). The stability of alanine transaminase (ALT) in serum samples stored at 25ºC was for 24 h and for LDH was for 48 h at 4ºC. Aspartate transaminase (AST) was the most unstable analyte at different storage times at both temperatures. Urea, TP, ALB, TB, and P were stable at 4ºC for as long as 6 h. Creatinine and ALP were affected by 24 and 48 h storage times at both temperatures. There was a significant difference (P 0.05) in AST and ALT activities between two temperatures. No significant difference was observed in creatinine, urea, and TB concentrations between two storage temperatures at any of the storage times. CONCLUSIONS: This study showed that some analytes have acceptable stability in the clotted blood samples stored at 4°C for 6 h.