Comparative Evaluation of the Effects of Serum Separator Tubes and Transport Systems on Hormone and Tumor Marker Measurements.

Abstract

Background Controlling pre-analytical factors ensures the accuracy of hormone and tumor marker assays. We evaluated the combined effects of using different serum separator tubes (i.e., Ampulab [Soyagreentec]), Vacutainer [Becton Dickinson], and Vacuette [Greiner Bio-One]) and transport methods (i.e., the AirLab high-speed pneumatic tube system [PTS; PazKorea] and a conveyor system) on measurement results of 20 analytes. Methods Blood was collected from 57 volunteers and equally distributed into six tubes per participant to cover all possible tube type-transport system combinations. Twenty analytes were measured using Cobas e801 (Roche Diagnostics) and UniCel DXI 800 (Beckman Coulter) analyzers. For each analyte, the same analyzer was used across all samples. To evaluate hemolysis in PTS-transported samples, hemolytic index, AST, potassium, and lactate dehydrogenase levels were measured using Cobas c702 (Roche Diagnostics). Clinically significant or important differences were defined as average percentage biases exceeding European Federation of Clinical Chemistry and Laboratory Medicine desirable and optimal bias criteria, respectively. Results Estradiol showed a clinically significant difference (-8.21%) in conveyor-transported Vacutainer versus Vacuette tubes and clinically important difference between Ampulab and other tubes as separator gel adsorption was different. Insulin exhibited a clinically important negative bias (-6.83%) in PTS-transported Vacuette tubes owing to insulin-degrading enzyme release from hemolyzed erythrocytes. No other analytes exhibited clinically significant or important differences. Vacuette tubes were the most susceptible to PTS-induced hemolysis, corresponding to the largest insulin bias. Conclusions Ampulab tubes and the AirLab system performed comparably to their comparators, though caution is warranted for estradiol and insulin results.