title: A simple, automated, nonextraction assay for serum digoxin using particle-enhanced immunoassay.
abstract: We have adapted a latex particle-enhanced immunoassay for serum digoxin to a centrifugal analyser. A 4-microliter serum sample (without pretreatment) inhibits the monoclonal antibody induced aggregation of digoxin-coated latex particles. The total assay time is 10 min and mean analytical recoveries were 98.1%. Intra and interassay precision were < 4.2 and < 15.0%, respectively. Method comparison with an established fluorescence polarisation immunoassay (FPIA) gave R = 0.97, and a Deming regression analysis of particle-enhanced turbidimetric inhibition immunoassay (PETINIA) = FPIA x 0.78 + 0.007 microgram/L (n = 91). There was no evidence of significant interference from digoxin-like immunoreactive compounds in patients with chronic renal failure. This assay can be adapted to most photometric analysers used in routine laboratories and is a significant advance in the sensitivity of latex particle-enhanced immunoassays in a serum matrix.
authors.affiliation: Department of Clinical Biochemistry, St. Bartholomew's and the Royal London School of Medicine and Dentistry, England.
authors.forename: C L
authors.initials: CL
authors.lastname: Davey
authors.forename: H
authors.initials: H
authors.lastname: Thakkar
authors.forename: D J
authors.initials: DJ
authors.lastname: Newman
authors.forename: C P
authors.initials: CP
authors.lastname: Price
mesh_terms: D002316:Cardiotonic Agents / Q000097:blood*; D004077:Digoxin / Q000097:blood*; D006801:Humans; D007118:Immunoassay / Q000379:methods; D007840:Latex; D009391:Nephelometry and Turbidimetry; D015203:Reproducibility of Results
chemical_list: D002316:Cardiotonic Agents; D007840:Latex; D004077:Digoxin