Effects of haemolysis and prolonged cold storage of human plasma on the α-atrial natriuretic peptide concentration

Monoclonal Antibodies

“…Most extraction methods isolated sufficient ANP from 1-2 ml plasma for measurement by RIA (Yamaji et al, 1985;Gutkowska et al, 1987;Burrell et al, 1990) although some extractions required 5-15 ml plasma (Arendt et al, 1985;), while the methods described by Tordk and Penke (1991) and Iinuma et al (1987) needed only 0.25 ml and 0.5 ml plasma, respectively, because they were combined with sensitive RIAs. Prompt extraction was important because ANP was unstable in plasma (Nishiuchi et al, 1986;Richards et al, 1987b;Artner-Dworzak et al, 1991) and serum , even during storage at -80°C (Lijnen et al, 1988;Burrell et al, 1990;Nelesen et al, 1992), and ANP activity was also decreased by freeze-thawing (Biirgisser et al, 1985;Tan et al, 1990). After extraction, the solvent was usually removed by evaporation (Richards et al, 1987b;Burrell et al, 1990) or lyophilization (Yamaji et al, 1985;Sarda et al, 1989), a step which increased the total preparation time significantly and which was unnecessary in some methods (Iinuma et al, 1987;Torok and Penke, 1991).…”

Plasma atrial natriuretic peptide is unstable under most storage conditions.

“…[5][6][7][8][9] Various reports have suggested that ANP levels remain stable from as little as 3 days to as long as 6 months. Furthermore, these studies have examined ANP levels from normal volunteers, whose ANP concentrations are so low as to be near the sensitivity limits of the assay.8,9…”