[Varying standard concentrations as a cause of divergent serum digoxin estimations using radioimmune-essays (author's transl)].

1. The results of various commercial radio-immune essays for digoxin differ and cannot readily be compared. 2. For each RIA it is therefore necessary to determine one's own therapeutic and toxic levels in relation to the clinical requirements. 3. When quoting data, it is necessary to define the method of RIA with its therapeutic and toxic levels. 4. A cause for the high digoxin estimations of 2 RIA's carried out by the same firm has been identified as being due to the low concentration of the standard preparation. 5. The introduction of a defined and obligatory digoxin standard is recommended.