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

Abstract

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. 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. 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 8hours postcollection. Glucose concentrations were compared using linear mixed models. 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 2hours in sturgeon and alpaca, but significantly lower at 4 and 8hours in those species, and at all time points in equine and canine specimens, being most prominent after 8hours of storage in canine specimens. Storage at 4°C limits serum glucose decline for at least 4hours in all species tested and up to 8hours in specimens of horse and alpaca. At 25°C, serum-clot contact time should not exceed 1hour in equine and canine samples, and 2hours in specimens from alpaca and sturgeon.