A sensitive enzyme immunoassay for atrial natriuretic polypeptide

Abstract A sensitive sandwich enzyme immunoassay for mammalian α-atrial natriuretic polypeptide (α-ANP) has been developed using Fab′ fragments of affinity purified rabbit anti-α-hANP[6–28] polyclonal antibodies (R3) conjugated to horseradish peroxidase. Immunoplates were coated with (F(ab′) 2 ) fragments of anti-α-hANP monoclonal antibodies (HA53). Without using a pre-concentration step the detection limit of α-hANP in plasma was 5 pg/ml. The assay was sufficient accuracy and reproducibility for general use of, i.e., the coefficients of within-assay and between-assay variation were 6.4 ∼ 10.7% and 9.7 ∼ 15.3%, respectively. Using the assay, the basal plasma α-hANP level of healthy persons was 15.3 ± 8.3 pg/ml (mean ± SD, n = 40).