The clinical usefulness of a microparticle enzyme immunoassay (MEIA) method for the determination of dogoxin in serum was investigated. The inter-and intra-assay reproducibilities of this method were 2.4 to 4.9% and 3.8 to 6.2%(C.V.%), respectively.In the determination of serum digoxin levels, MEIA well correlated with fluorescence polarization immunoassay (FPIA) (r=0.942, n=153). Cross reaction by various drugs used concomitantly with digoxin was not detected in the MEIA assay. Moreover, endogenous digoxin-like immunoreactive substance was not detected in serum from newborns (n=24) or patients with renal failure (n=42) who were not taking digoxin.
