Serum digoxin in the presence of digibind: determination of digoxin by the Abbott AxSYM and Baxter Stratus II immunoassays by direct analysis without pretreatment of serum samples.

We have reevaluated the feasibility of using direct immunochemical methods to track free digoxin in patients receiving Digibind. We report here that results obtained by the Stratus II and AxSYM immunoassays on patients receiving digoxin (without Digibind), digoxin-fortified serum samples supplemented with Digibind, and a digitoxic patient treated with Digibind, show no clinically significant biases. We conclude that useful free digoxin concentrations may be obtained for Digibind-treated patients using either the AxSYM or Stratus immunoassays without subjecting samples to ultrafiltration before analysis.