Development of Radioimmunoassay for Measurement of Serum Digoxin in Digitalized Patients Using Novel Anti-digoxin Antiserum

There is an antiserum elicited by digoxin 3′-hemisuccinate–bovine serum albumin (BSA) conjugate possessing high specificity for digoxin. Our study focused on development of RIA using this novel antiserum for measurement of digoxin in serum from digitalized patients. The property of the new antiserum was investigated by RIA with digoxin 3′-hemisuccinyl-[3H]leucine. The separation of bound and free fractions was performed using a dextran-coated charcoal suspension. The new antiserum bound approximately 50% of digoxin 3′-hemisuccinyl-[3H]leucine with a final dilution of 1 : 30000. The intra- and inter-assay coefficients of variation were