RESUMO
AIMS: To explore differences in B-type natriuretic peptide (BNP) concentration and stability and evaluate BNP accuracy in different collection tubes. METHODS: BNP concentrations in heparin/glass, EDTA/glass, and EDTA/polyethylene terephthalate (PET) tubes were measured on the Mindray CL-6000i at 0.5, 1, 2, and 4 h after collection. Differences were evaluated using Wilcoxon's paired tests and Bland-Altman plots. BNP stability and measurement accuracies were estimated using Kruskal-Wallis H tests and recovery tests. RESULTS: BNP concentrations in EDTA/glass tubes were 31.4% higher than those in heparin/glass tubes and 3.04% lower than those in EDTA/PET tubes. BNP stability significantly decreased in the heparin/glass tube. BNP remained stable in EDTA/glass and EDTA/PET tubes at room temperature for 4 h. BNP recovery rates in heparin/glass, EDTA/glass, and EDTA/PET tubes were 77.46, 86.04, and 88.23%, respectively. CONCLUSIONS: Plasma in EDTA/glass and EDTA/PET tubes is suitable for BNP measurement on the Mindray CL-6000i.