An automated, affinity-column-mediated, enzyme-linked immunometric assay for digoxin on the Du Pont aca discrete...

We describe an automated assay for digoxin that requires a 200-microL sample of serum. Total analysis time is 18 min. The method is extremely precise, with within-run CVs of 2.6, 1.6, and 4.9%, respectively, at 0.5, 1.5, and 3.5 micrograms of digoxin per liter (n = 20). The lower limit of detection is 0.2 micrograms of digoxin per liter. For patients' samples, the correlation with RIA (x) is excellent (r = 0.95; y = 0.95x - 0.14; standard error = 0.17 micrograms/mL). We saw no interferences in samples having high concentrations of rheumatoid factors, lipid, bilirubin, or hemoglobin. Cross reactivity with digoxin analogs and steroidal compounds is similar to that observed by RIA.