[Clinical value of the determination of serum digoxin levels (author's transl)].

The authors refer to the technique of the serum digoxin enzyme immunoassay, and they report the results of 297 dosages concerning 111 hospitalized patients. The normal plasmatic rates are of 1,4 +/- 0,6 microgram/l in patients who present no sign of digitalic overdosage. The rates are of 5,2 +/- 1,6 microgram/l in cases of intoxication. The difference between these rates is greatly significant (p less than 0.001). The limit between therapeutic and toxic rates is situated around 3 microgram/l with an overlapping from 2 to 3 microgram/l. Authors then examine the individual factors that intervene in digoxin metabolism and especially study the influence of age, myocardic factors and renal insufficiency. On the basis of these results and review of the literature, they emphasize the interest of serum digoxin determination in the diagnosis of digitalis toxicity, as well as in the management of high risk patients, and of cardiopathies difficult to stabilize.