Stability of plasma concentrations ofN and C terminal atrial natriuretic peptides

Background-Plasma concentrations of atrial natriuretic peptide (ANP) are increased in patients with ventricular dysfunction and could have a diagnostic role in heart failure. ANP may be unstable after collection, however, limiting any practical diagnostic role. Methods-Blood samples were obtained from 18 patients with various conditions. Aliquots were either processed optimally or kept as blood or plasma at room temperature for 6-72 h before processing. Results-Concentrations of C-terminal ANP were lower in specimens kept as blood for 24 and 72 h (mean difference from control 43% and -76%, respectively, (P < 0.001) but N-terminal ANP (extracted) seemed to be stable under all conditions studied (2% at 24 h and 7% at 72 h, not significant). Conclusions-N-terminal ANP (extracted) is stable and potentially has a role in the diagnosis of heart failure in routine clinical practice. (Heart 1996;75:410-413)