title: Competitive solid-phase immunoassay of gastrin in serum using time-resolved fluorometry.
abstract: BACKGROUND
  A competitive solid-phase assay for the measurement of gastrin in serum using time-resolved fluorescence was developed as an alternative to conventional radioimmunoassay (RIA) technology.
  
  
  METHODS
  The assay depends on the competitive binding of unlabelled versus Eu-labelled gastrin to specific gastrin antibodies--bound to anti-rabbit IgG immobilized on polystyrene microtitration strips. The bound Eu(3+)-label was dissociated from the bound gastrin and converted to a fluorescent β-diketone chelate which was measured by fluorometry with time-resolution.
  
  
  RESULTS
  Using a sample volume of 50 μl the lower limit of detection was below 10 pmol/L. Dilution of samples showed an excellent linearity. Spiking with gastrin-17 in known concentrations showed a recovery of 103% indicating that there is no bias inherent in the assay. The method correlated fully with the routine in-house radioimmunoassay in the concentration range 10-400 pmol/L (slope = 0.98 with r(2) = 0.98). Thus the reference interval for clinical samples does not require modification when changing from one method to the other.
  
  
  CONCLUSIONS
  We have described a convenient and accurate competitive assay for measurement of gastrin in serum based on solid-phase technology using time-resolved fluorometric detection as a realistic alternative to the established state-of-the-art RIA-technology.
authors.affiliation: Department of Clinical Biochemistry, Rigshospitalet, University of Copenhagen, Denmark. anders.johnsen@rh.regionh.dk
authors.forename: Anders H
authors.initials: AH
authors.lastname: Johnsen
authors.forename: Fahed N
authors.initials: FN
authors.lastname: Assaad
authors.forename: Jens F
authors.initials: JF
authors.lastname: Rehfeld
mesh_terms: D000818:Animals; D005470:Fluorometry; D005755:Gastrins / Q000097:blood*; D006801:Humans; D007106:Immune Sera; D007118:Immunoassay / Q000379:methods; D011817:Rabbits; D015043:Zollinger-Ellison Syndrome / Q000175:diagnosis
chemical_list: D005755:Gastrins; D007106:Immune Sera