Stability of 27 biochemistry analytes in storage at a range of temperatures after centrifugation

Knowledge of factors affecting sample integrity is vital to make informed judgements on the validity of results. However, the information available for sample stability is incomplete, confusing and conflicting, particularly post-centrifugation. This study aims to investigate the effects of storage conditions on biochemical analytes. As part of this study, a new method has been developed, based on the manufacturer's stated analytical precision for the methodology. Ten adult volunteers were recruited into the study. Blood was collected into serum-separating tubes, and allowed to clot at room temperature for 30 minutes. After centrifugation, serum samples were stored frozen, refrigerated or at ambient temperature for between two hours and three months. After the allotted time had elapsed, designated serum aliquots were stored at -80 degrees C, before batch analysis for 27 biochemical analytes. Twenty-three out of the 27 analytes remained stable until the last time-point tested at all temperature conditions. Alanine aminotransferase (ALT), lactate dehydrogenase (LD-P), potassium and uric acid showed reduced stability with at least one of the storage conditions tested. The method developed provided robust sample stability data within the inherent imprecision of the assay(s) used. The results generated can be used to create an evidence-based policy recommending sample handling and transportation practices that will ensure optimal sample integrity, and permit informed judgements to be made on results of stored samples. Minimal effects on sample stability were noted for the majority of analytes using the storage conditions tested in this study.