title: Radioimmunoassay for plasma C-type natriuretic peptide determination: a methodological evaluation.
abstract: C-Type natriuretic peptide (CNP) is a member of the family of natriuretic peptides with vasodilatory properties, and is produced and secreted by endothelial cells. It seems to play a central role in the paracrine vasomotor control of tone and to be important in several clinical conditions characterized by endothelial dysfunction. We evaluated the analytical performance of a commercially available radioimmunoassay for CNP after a preliminary extraction with Sep-Pak C18. Its analytical reliability was checked by determination of CNP plasma levels in healthy subjects (n = 23) and in patients with different diseases, likely characterized by endothelial dysfunction, such as chronic heart failure (n = 133) and cirrhosis (n = 84). The extraction yield was 78+/-3%. Accuracy of the radiommunological determination was evaluated by dilution (45-370 microL of extracted plasma) and recovery tests (>80%). Between- and within-assay variabilities were < or = 10% and analytical sensitivity was 0.41+/-0.015 pg/tube. Plasma CNP in patients with chronic heart failure and with cirrhosis was significantly raised compared to controls (p<0.0001 and p = 0.001, respectively). The sensitivity, accuracy and variability levels of the method proposed for CNP assay was suitable for reliable detection of changes in CNP plasma levels in the clinical setting.
authors: CNR Institute of Clinical Physiology, Pisa, Italy.
authors: Silvia
authors: S
authors: Del Ry
authors: Maristella
authors: M
authors: Maltinti
authors: Michele
authors: M
authors: Emdin
authors: Claudio
authors: C
authors: Passino
authors: Giosué
authors: G
authors: Catapano
authors: Daniela
authors: D
authors: Giannessi
mesh_terms: D000368:Aged; D003429:Cross Reactions; D005260:Female; D005355:Fibrosis / Q000097:blood; D006333:Heart Failure / Q000097:blood; D006801:Humans; D008297:Male; D008722:Methods; D008875:Middle Aged; D020098:Natriuretic Peptide, C-Type / Q000097:blood*; D011863:Radioimmunoassay / Q000379:methods* / Q000592:standards; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013045:Species Specificity
chemical_list: D020098:Natriuretic Peptide, C-Type