Spironolactone-associated digoxin radioimmunoassay interference. [/sup 3/H, /sup 125/I tracer techniques]

Journal Article · Mon Jan 01 04:00:00 EST 1979 · Clin. Chem.; (United States)

OSTI ID:6368496

Silber, B; Sheiner, L B; Powers, J L; Winter, M E; Sadee, W

Apparent digoxin was measured in the serum of 21 patients receiving spironolactone and in 21 controls, by use of a sequential-saturation /sup 3/H-radioimmunoassay (RIA) and an equilibrium /sup 125/I-RIA. No patient had been given digoxin for at least four weeks. ''Digoxin'' values in the former group were significantly (p < 0.05) higher than in the control group, and often were in or near the ''therapeutic'' range by the equilibrium /sup 125/I-RIA, but not by the sequential-saturation /sup 3/H-RIA. Canrenone (a major active metabolite of spironolactone) in the serum of the former group was measured by a newly developed liquid-chromatographic technique and correlated (r = 0.73) with ''digoxin'' concentrations by the /sup 125/I-RIA. However, external addition of canrenone to control serum in comparable concentrations did not cause appreciable ''digoxin'' values by the /sup 125/I-RIA. These findings suggest that other metabolites of spironolactone are responsible for the assay interference, the degree of which appears to depend on antibody specificity. Therefore, assay specificity should be established in clinical laboratories by using digoxin-free serum from patients ingesting spironolactone, and not by using spironolactone- or canrenone-fortified digoxin-free serum.

• Research Organization: Univ. of California, San Francisco
• OSTI ID: 6368496
• Journal Information: Clin. Chem.; (United States), Journal Name: Clin. Chem.; (United States) Vol. 25:1; ISSN CLCHA
• Country of Publication: United States
• Language: English

Related Subjects

550601* -- Medicine-- Unsealed Radionuclides in Diagnostics
62 RADIOLOGY AND NUCLEAR MEDICINE
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOLOGICAL EFFECTS
CARBOHYDRATES
CARDIOTONICS
CHROMATOGRAPHY
DAYS LIVING RADIOISOTOPES
DIGITALIS GLYCOSIDES
DIGOXIN
DRUGS
ELECTRON CAPTURE RADIOISOTOPES
ESTERS
GLYCOSIDES
HETEROCYCLIC COMPOUNDS
HYDROGEN ISOTOPES
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
LACTONES
LIGHT NUCLEI
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
PATIENTS
RADIOASSAY
RADIOIMMUNOASSAY
RADIOISOTOPES
SEPARATION PROCESSES
STEROIDS
TRACER TECHNIQUES
TRITIUM
YEARS LIVING RADIOISOTOPES