Fluorescence energy transfer immunoassay of digoxin in serum.

We have evaluated the reliability of the new fluorescence energy transfer immunoassay (FETI) for determining concentrations of digoxin in serum. The method demonstrated good stability of the standard curve and satisfactory precision in both within-and between-run assay. We have also found a significant correlation between FETI and two RIA methods (r=0.97). Furthermore, the association between results by FETI and by the EMIT method (a conventional enzyme immunoassay) was a linear one. Finally, the assay encountered no significant interference from endogenous substances (hemoglobin, bilirubin , and triglycerides).