Assessment of the stability of 20 biochemical analytes in serum and whole blood samples after storage at nonstandard temperatures.

Background: Blood specimen transport conditions can have critical impacts on analyte stability and test result accuracy. This study evaluated the impact of multiday storage of specimens at 30 °C and 0 °C, approximating shipment under summer conditions and shipment in contact with melting ice, respectively. Methods: Blood samples from 16 healthy subjects were processed as serum samples and as clotted whole blood (uncentrifuged) stored at 30 °C on separator gel, and as serum stored in microtainers at 0 °C, each for 24- and 72-h periods prior to analysis. Each sample was analyzed for 20 common analytes and compared to the values from a paired baseline control sample. Mean absolute and/or relative biases were calculated and compared to CLIA acceptance limits. Results: Serum samples stored at 30 °C for 24- or 72-h met acceptance criteria for all assessed analytes, except for 72-h ALT, Total Bilirubin, Carbon Dioxide, Creatinine, and Sodium. Numerous analytes were unstable at 30 °C in uncentrifuged whole blood, with only Albumin, ALP, Total Bilirubin, Cholesterol, HDL, Total Protein, Triglycerides, Uric Acid, and hsCRP remaining stable up to 72 h. For serum samples stored at 0 °C, all 24- hour and 72-h analytes showed biases within limits. Conclusion: Storage of serum samples at 0 °C for up to 72 h yielded valid results for all analytes studied. Storage at 30 °C for up to 72-h yielded valid results for most analytes when combined with centrifugation prior to storage. Compared to room temperature storage, ALT and Sodium in serum and whole blood showed signs of accelerated degradation at 30 °C.