Comparison of Barricor™ vs. lithium heparin tubes for selected routine biochemical analytes and evaluation of post centrifugation stability

INTRODUCTION: Obtaining suitable results unaffected by pre- or postanalytical phases is pivotal for clinical chemistry service. We aimed comparison and stability of nine biochemical analytes after centrifugation using Barricor™ plasma tubes with mechanical separator vs standard Vacutainer® lithium heparin tubes. MATERIALS AND METHODS: We collected samples on six healthy volunteers and nine patients from intensive care units into 6 mL plastic Vacutainer® lithium heparin tubes and 5.5 mL plastic Barricor™ plasma tubes. All tubes were centrifuged within 30 minutes after venipuncture. First, we compared results of nine biochemical analytes from lithium heparin tubes with Barricor™ tubes for each analyte using Passing-Bablok and Bland-Altman analyses. Second, we calculated the difference of analyte concentrations between baseline and time intervals in tubes stored at + 4 °C. Based on the total change limit we calculated the maximum allowable concentrations percentage change from baseline. RESULTS: The majority of correlation coefficients were close to 0.99 indicating good correlation in the working range. Bland-Altman analyses showed an acceptable concordance for all analytes. In consequence, the Barricor™ tube might be an alternative to regular lithium heparin tube. Stability with this new generation tube is improved for eight analytes (except for aspartate aminotransferase) in comparison with regular lithium heparin tubes. CONCLUSIONS: By using Barricor™ tubes and prompt centrifugation, supplemental analysis or re-analysis for eight analytes including alanine aminotransferase, alkaline phosphatase, C-reactive protein, high sensitivity troponin T, lactate dehydrogenase, NT-pro BNP, potassium and sodium could be performed within 72 h of specimen collection.