STUDIES ON DIGITALIS .19. DIGITALIS GLYCOSIDES IN SERUM, URINE, AND CEREBROSPINAL-FLUID, DETERMINED WITH A COMMERCIAL RADIOIMMUNOASSAY

  • 1 January 1980
    • journal article
    • research article
    • Vol. 26  (2) , 321-323
Abstract
A commercial (Clinical Assays, Inc.) 125I radioimmunoassay for digitoxin for use in measuring cardiac glycosides in human serum, buffer, urine and CSF was evaluated. Interference of 7 cardioactive metabolites of digitoxin, including digoxin, was studied with the assay. The precision of the assay was adequate for all matrixes studied for glycoside concentrations < 5 .mu.g/l. Reactivity in the assay was dependent on the nature of the matrix: buffer and serum samples containing digitoxin showed a stronger reactivity than did samples of urine and CSF. Patients'' samples must be analyzed with a standard curve prepared by use of the same matrix. The digitoxosides of digitoxin showed a slightly higher reactivity in the assay than did digitoxin itself, but digitoxigenin showed a 50% lesser reactivity. Digoxin, its digitoxosides and digoxigenin hardly react at all in the assay and so do not interfere with digitoxin determinations.