摘要：A digoxin radioimmunoassay (RIA) or fluorescence polarization immunoassay (FPIA) kit is frequently used in routine therapeutic drug monitoring (TDM) of β-methyldigoxin (MD) by applying a calibration curve made using the corresponding digoxin calibrators. The variances in the plasma levels (61 samples) and pharmacokinetics (5 patients) due to these two different assay methods for MD were examined in our patients with congestive heart failure. Although the plasma levels of MD measured by these methods were well correlated (r=0.956, p<0.001) to each other over a wide range, RIA showed significantly lower values (p<0.01) in the subtherapeutic range (<0.80 ng/ml), but significantly higher values (p<0.002) in the therapeutic and toxic ranges (0.80-2.00 and 2.00
