Stabilization of human brain natriuretic peptide in blood samples.

Fig. 1. StabilIty of hBNP in whole-blood samples at 25#{176}C (A) and 4#{176}C (B). Samples were collected from three apparently healthy male volunteers (ages25-27 years) Into 50-mL plastic syringesand quickly transferred to ice-chilledplastic tubes containing EDTA-Na, (1.5 g/L) and hBNP-32 (170 ng/L, 49.1 pmol/L).The tubes also contained aprotlnin (500 KIU/mL, ) phosphoramidon 110.9gIL (20 nmol/L), J, or no additives (0) in (A), and aprotinin (500 KIU/mL #{149}), aprotinin (500 KIU/mL) plusphosphoramidon (20nmol/L) (#{149}), or aprotinln (500 KIU/mL) plus benzamidine (100 mmol/L) () in (B). The blood samples were transported on ice within 30 mmand werethenkeptat 25’C (A) or 4#{176}C (B) for 0, 3, 24, or 48 h. After this, 1-mL aliquots were withdrawn and centrifuged at 1600g and 4’C for 20 mm. The resulting plasma samples were kept frozen at -80#{176}C until determination. hBNP-32-likeimmunoreactivity was determinedwith the IRMA described elsewhere(6). The data representmean ± SD of three determinations.