Plasma and myocardial digoxin concentrations in patients on oral therapy.

Abstract

Methods are now available which are sensitive enough to detect digoxin concentration to levels of 5 mug./ml. Hitherto the degree of sensitivity of specific chemical methods was not acceptable for clinical application. Digoxin-specific antibodies have recently been prepared (Butler and Chen, 1967), and a test based on the radioimmunoassay principle has now been used to measure plasma digoxin levels (Oliver et al., 1968). The double isotope dilution technique is a specific and very sensitive method for measuring steroids in biological extracts, and it has been applied successfully to determining plasma digitoxin levels in man (Lukas and Peterson, 1966). However, there are no reports on its use for measuring plasma digoxin.