STABILITY OF PLASMA-CONCENTRATIONS OF N-TERMINAL AND C-TERMINAL ATRIAL NATRIURETIC PEPTIDES AT ROOM-TEMPERATURE

Background-Plasma concentrations of atrial natriuretic peptide (ANP) a re increased in patients with ventricular dysfunction and could have a diagnostic role in heart failure. ANP may be unstable after collectio n, however, limiting any practical diagnostic role. Methods-Blood samp les were obtained from 18 patients with various conditions. Aliquots w ere either processed optimally or kept as blood or plasma at room temp erature for 6-72 h before processing. Results-Concentrations of C-term inal ANP were lower in specimens kept as blood for 24 and 72 h (mean d ifference from control -43% and -76%, respectively, (P < 0.001) but N- terminal ANP (extracted) seemed to be stable under all conditions stud ied (-2% at 24 h and -7% at 72 h, not significant). Conclusions-N-term inal ANP (extracted) is stable and potentially has a role in the diagn osis of heart failure in routine clinical practice.