Performance of a manually operated salad spinner centrifuge for serum separation in the healthy domestic horse (Equus caballus) and southern white rhinoceros (Ceratotherium simum).

Background: Field veterinarians and researchers studying wild species, such as the southern white rhinoceros, often work in remote areas with limited access to standard laboratory equipment, hindering the ability to measure serum analytes.

Objectives: The first objective was to produce an inexpensive, manually operated centrifuge that could accept standard laboratory tubes by modifying a consumer-grade salad spinner with low-cost materials. The second objective was to compare biochemistry analysis results obtained from equine and southern white rhinoceros serum separated by traditional laboratory and manual salad spinner centrifugation.

Methods: We optimized the design and serum separation protocol using non-anticoagulated equine blood. Equine and rhinoceros serum samples were separated by manual salad spinner or traditional laboratory centrifugation. Measured analytes included sodium, potassium, chloride, urea nitrogen, creatinine, phosphorous, total calcium, magnesium, glucose, total protein, albumin, globulin, creatinine kinase, aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, gamma-glutamyl transferase, total bilirubin, bicarbonate, sorbitol dehydrogenase, and triglycerides. Results obtained from serum separated by each centrifugation technique were compared by Deming regression and Bland-Altman analyses.

Results: A tube adaptor insert modeled after a swing angle rotor and a two-step salad spinner centrifugation yielded serum comparable to traditional laboratory centrifugation. For the majority of analytes, no proportional or constant biases were detected between centrifugation methods. A positive proportional bias in the measurement of ALP in serum separated by manual centrifugation was detected in both equine and rhinoceros samples.

Conclusions: Manual centrifugation with a modified salad spinner yields diagnostic quality serum suitable for the measurement of most standard biochemistry analytes.