Effect of delayed serum separation and storage temperature on serum glucose concentration in horse, dog, alpaca, and sturgeon.

Abstract

BACKGROUND: Although delays between blood sample collection and analysis are common in veterinary medicine, the effect of prolonged serum-clot contact time on serum glucose concentration is not well established and species differences have not been elucidated. OBJECTIVES: The objective was to investigate the effect of storage time and temperature on serum glucose concentration in stored whole blood samples from horse, dog, alpaca, and sturgeon. METHODS: Whole blood specimens were divided into 7 no-additive tubes and serum was separated from one sample within one hour, serving as the reference sample. The remaining samples were stored at 4°C and 25°C, then centrifuged and serum glucose measured by automated analysis at 2, 4, and 8 hours postcollection. Glucose concentrations were compared using linear mixed models. RESULTS: The decline in serum glucose concentration for all samples stored at 4°C was not statistically significant, except for the 8-hour samples from sturgeon and dog. At 25°C, serum glucose concentration was comparable to reference values at 2 hours in sturgeon and alpaca, but significantly lower at 4 and 8 hours in those species, and at all time points in equine and canine specimens, being most prominent after 8 hours of storage in canine specimens. CONCLUSIONS: Storage at 4°C limits serum glucose decline for at least 4 hours in all species tested and up to 8 hours in specimens of horse and alpaca. At 25°C, serum-clot contact time should not exceed 1 hour in equine and canine samples, and 2 hours in specimens from alpaca and sturgeon.