Lack of endogenous crossreactivity with three digitoxin radioimmunoassays in adults with renal insufficiency
Mueller, B.A.; Bussey, H.I.; Casto, D.T.; Lowder, N.K.; Sugarek, N.J.; Cremer, K.F.
Clinical Pharmacy 7(11): 825-828
1988
ISSN/ISBN: 0278-2677 PMID: 3197382 Document Number: 322362
The possibility of interference by apparent digitoxin-like immunoreactive substance (DTLIS) with three radioimmunoassays was studied in patients with renal insufficiency. From each of 25 adult patients with renal insufficiency and 25 age-matched and sex-matched control subjects with normal renal function, a single serum sample was obtained and assayed for digitoxin content by three commercially available radioimmunoassays (GammaCoat, Coat-A-Count, and the Wien assay). Although two of the three assays found measurable concentrations, the difference in apparent digitoxin concentrations between the control subjects and those with renal insufficiency was not significant. Assay interference could not be explained on the basis of differences in age, serum creatinine concentration, or weight. The magnitude of DTLIS interference in relation to the digitoxin therapeutic range appears to be small with the readioimmunoassays used in this study.