Comparison of four digoxin immunoassays with respect to interference from digoxin-like immunoreactive factors

• Published in: Clinical biochemistry Vol. 29; no. 6; pp. 541 - 547
• Main Authors: Datta, Pradip, Hinz, Vicki, Klee, George
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.12.1996
• Subjects: Adult; Antibodies; Antibodies, Monoclonal; Cross Reactions; Cross-reactivity; Digoxin - blood; Digoxin - therapeutic use; Digoxin immunoassays; Digoxin-like immunoreactive factors; Female; Fluoroimmunoassay; Humans; Immunoassay - methods; Infant, Newborn; Kidney Diseases - blood; Kidney Diseases - drug therapy; Liver Diseases - blood; Liver Diseases - drug therapy; Luminescent Measurements; Male; Organ Transplantation; Pregnancy; Radioimmunoassay; Sensitivity and Specificity; Specificity; Antibodies; Specificity; Digoxin-like immunoreactive factors; Digoxin immunoassays; Cross-reactivity
• ISSN: 0009-9120; 1873-2933
• DOI: 10.1016/S0009-9120(96)00100-2

Objectives: Comparison of a new monoclonal digoxin assay with three polyclonal digoxin assays for their cross-reactivity to digoxinlike immunoreactive factors (DLIF) and digoxin metabolites. Design and Methods: Sixty-:six nondigitalized patient samples from 5 different groups: neonates, women in 3rd trimester pregnancy, and patients with liver or renal diseases, or undergoing organ transplants, and 139 samples from digoxin-treated patients of 4 categories (hospital sick, liver, renal, and outpatients) were compared in 4 different digoxin assays: (a) ACS™ Digoxin (ACS) developed for the automated chemiluminescent Ciba Corning ACS 180 ® system, (b) Baxter Stratus™ (Stratus, a fluoroimmunoassay), (c) Ciba-Corning Magic TM (Magic, a radioimmunoassay), and (d) an in-house radioimmunoassay (RIA). The ACS TM and RIA were also compared for their cross-reactivity to four principal digoxin metabolites. Results and Conclusion: Among the nondigitalized specimens, no significant DLIF interference was found for all 4 assays among the pregnant women or liver and transplant patients. However, the neonates registered high DLIF interference with Magic™ and RIA, but none for ACS™ or Stratus™. DLIF interference in renal samples was highest in the Magic assay and lowest in RIA. Among the specimens with digoxin, a higher number of discrepant samples were found from the sick patients than from outpatients. In 75% of such discrepant samples, the ACS™ result was less than other assay results, suggesting DLIF as the probable cause. The two assays differed most in their cross-reactivity to the deglycated metabolites, digoxigenin and its mono-digitoxoside.