title: Analytical and clinical validation of a radioimmunoassay for the measurement of 1,25 dihydroxy vitamin D.
abstract: OBJECTIVE
  The analytical and clinical validation of the DiaSorin 1,25 dihydroxyvitamin D RIA is described.
  
  
  METHODS
  The analytical parameters assessed included analytical sensitivity, dilution linearity, intra- and inter-assay precision, recovery, specificity, and interference studies. Where appropriate, assessments were performed according to NCCLS guidelines. The clinical validation assessed normal individuals and end-stage renal disease patients.
  
  
  RESULTS
  The analytical sensitivity of the assay is < 2.0 pg/mL or < 4.8 pM. The assay is specific for both 1,25 dihydroxyvitamin D2 and D3. Recovery ranged from 97% to 108% for spiked samples. Intra-assay precision, as %CV, ranged from 7% to 11%, while inter-assay precision was 12% to 15%. No interference was observed from bilirubin, cholesterol, hemoglobin, or triglycerides. Clinical validation demonstrated complete discrimination between normal and ESRD populations.
  
  
  CONCLUSIONS
  These data demonstrate that the DiaSorin 1,25 (OH)(2) vitamin D RIA is a robust, accurate, and precise tool for the assessment of 1,25 (OH)(2) vitamin D.
authors.affiliation: DiaSorin, Inc., Stillwater, MN 55082, USA.
authors.forename: Diana R
authors.initials: DR
authors.lastname: Clive
authors.forename: D
authors.initials: D
authors.lastname: Sudhaker
authors.forename: Donald
authors.initials: D
authors.lastname: Giacherio
authors.forename: Manjula
authors.initials: M
authors.lastname: Gupta
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Schreiber
authors.forename: James L
authors.initials: JL
authors.lastname: Sackrison
authors.forename: Gordon D
authors.initials: GD
authors.lastname: MacFarlane
mesh_terms: D006801:Humans; D007676:Kidney Failure, Chronic / Q000097:blood; D016014:Linear Models; D011863:Radioimmunoassay / Q000379:methods*; D012016:Reference Values; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013696:Temperature; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood*
chemical_list: D014807:Vitamin D; C097949:1,25-dihydroxyvitamin D