The purpose of this study was to determine the reliability of test results dependent upon blood and plasma sample stability when shipped by airfreight courier for reference laboratory assessment. Of particular interest was evaluation of von Willebrand profile assays and platelet dense granule storage pool analysis. Peripheral venous blood was obtained from healthy volunteers. von Willebrand factor (VWF) activity, VWF antigen, and factor VIII coagulant activity assays were performed immediately following venipuncture with additional aliquots of plasma frozen and stored at -70°C for subsequent analysis 48 hours later. One frozen aliquot was shipped via airfreight for analysis 48 hours later, with another frozen aliquot that remained on-site. Blood was also collected to enumerate platelet dense granules to determine whether shipment would affect results. Statistical analysis of all test results demonstrated significant correlation between immediately assayed samples and samples that were stored for 48 hours at -70°C ( P < .0001), or frozen and shipped on dry ice ( P < .0001) for analysis upon return to our laboratory. No difference was found in the mean number of platelet dense granules between samples retained in our laboratory or samples analyzed upon return of shipment ( P = .751).
Keywords: bleeding; blood coagulation factors; laboratory tests; platelet dysfunction; platelet storage pool.