Volume 19, Issue 4 (October 1974)
A Radioimmunoassay Technique for Digoxin in Postmortem Blood
In spite of the availability of purified digitalis fractions such as digoxin, treatment of congestive heart failure and arrhythmias with cardiac glycosides is attended by considerable risk of toxicity and even death. Beller et al  estimate that toxicity results in 8–20 percent of hospital patients taking digoxin, with a subsequent mortality of 7–50 percent. The development of a radioimmunoassay sufficiently sensitive to quantitate digoxin in serum or plasma during therapy  might be expected to improve the control of therapy in patients with absorption or excretion abnormalities, and Smith and Haber  reported that more than 85 percent of toxic cases could be distinguished from nontoxic ones by the plasma digoxin concentrations. However, more recently, Fogelman et al  found little increase in plasma digoxin in toxicity; mean plasma concentrations were 1.69 ± 1.29, 1.61 ± 0.79, and 1.41 ± 1.09 ng/ml in groups classified as toxic, possibly toxic, and nontoxic. The extensive overlap of the digoxin concentrations in these three groups suggests that sensitivity to digoxin is the main factor in determining the onset of toxicity.