Analytical and clinical validation of a radioimmunoassay for the measurement of 1,25 dihydroxy vitamin D

Clin Biochem. 2002 Oct;35(7):517-21. doi: 10.1016/s0009-9120(02)00378-8.


Objectives: The analytical and clinical validation of the DiaSorin 1,25 dihydroxyvitamin D RIA is described.

Design and 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.

MeSH terms

  • Humans
  • Kidney Failure, Chronic / blood
  • Linear Models
  • Radioimmunoassay / methods*
  • Reference Values
  • Reproducibility of Results
  • Sensitivity and Specificity
  • Temperature
  • Vitamin D / analogs & derivatives*
  • Vitamin D / blood*


  • Vitamin D
  • 1,25-dihydroxyvitamin D