Stability of some clinical biochemistry parameters in equine serum/plasma stored at refrigerator and room temperatures: a preliminary study

Accurate measurement of clinical biochemistry parameters is an essential tool for the correct interpretation of clinical biochemistry abnormalities. A general problem faced by most clinical laboratories is inability to process blood samples received late or submitted in large numbers. This delay in sample processing is usually unavoidable. This present study evaluated the stability of some biochemistry parameters in equine blood before and after storage at room (25 °C) and refrigerator (4 °C) temperatures. Five milliliters of blood were collected from external jugular veins of 17 apparently healthy adult horses kept at Obollo Afor horse lairage, Enugu State. The blood samples were collected into anti-coagulant glass test tubes and in non-anticoagulant glass test tubes to harvest plasma and serum respectively. Serum and plasma were analyzed shortly (0 h), and then after storage at refrigerator and room temperatures, at 24, 48, 72 h. Standard procedures were followed in the determination of plasma Malondialdehyde (MDA), plasma glucose, serum calcium, sodium, potassium, and uric acid concentrations. Comparisons to the fresh samples (hour 0) (P < 0.05) revealed that plasma MDA was stable for 48 h at both 4 and 25 °C; serum uric acid, potassium, and calcium were stable, less than 24 h post sample collection, at both 4 and 25 °C. Serum sodium and plasma glucose were stable at 4 °C for up to 72 h. The results of this study suggest that the ideal temperature for storage of equine serum/plasma for serum sodium and plasma glucose determinations is 4 °C. Plasma stored for 48 h at either 4 or 25 °C is suitable for malondialdehyde determination. Also, serum uric acid, potassium, and calcium determinations should be carried out immediately upon separation of clotted blood from serum so as to avoid obtaining erroneous result.