25-OH Vitamin D ELISA Kit


Human 25-OH vitamin D ELISA kit is a reliable quantitative procedure for measuring 25OH vitamin D, 25-hydroxyvitamin D2 and 25-hydroxyvitamin D3 (25OH-D2 and 25OH-D3) in human serum. This assay has a sensitivity detection limit of 2.81 ng/ml.


Vitamin D refers to a generic name which can be used to describe vitamin D2 (ergocalciferol l) and vitamin D3 (or cholecalciferol). These are a group of fat-soluble secosteroids that function in intestinal absorption of iron, zinc, magnesium, calcium and phosphate. Humans are able to naturally produce vitamin D3 when the skin is exposed to ultraviolet sun rays, it is synthesised in the skin using the cholesterol precursor 7-dehydrocholesterol. On the other hand, vitamin D2 is a synthetic product and can be predominately found as an additive in certain food for example milk.

The measurement of circulating 25-OH vitamin D has been used to provide the patients status of vitamin D and in diagnosing hypovitaminosis, other clinical applications for the quantification of 25-hydroxy vitamin D has been used is in the diagnosis and therapy control of osteomalacia, renal osteodystrophy, rickets and postmenopausal osteoporosis. Human vitamin D can be further metabolised in the liver via hydroxylation to 25-OH vitamin D (25-hydroxyvitamin D). This is a precursor for many other vitamin D metabolites, yet it shows limited activity by itself even though it is the major circulating metabolite of vitamin D.


All reagents supplied need to be stored at 2 °C – 8 °C, unopened reagents will retain reactivity until expiration date. Do not use reagents beyond this date.

  • Microtiterplate (96 breakable wells): Coated with 25OH vitamin D (monoclonal antibodies).
  • Calibrators 0-5: Concentration 0 – 120.0 ng/ml, made up from 25-OH vitamin D.
  • Controls 1 and Control 2: Containing human 25OH vitamin D.
  • Incubation Buffer.
  • Conjugate (100x Concentrated): Consisting of HRP labelled with anti human 25-OH vitamin D in stabilizing buffer.
  • Conjugate Buffer.
  • Concentrated HRP (200x).
  • Wash Solution (200x).
  • Chromogenic Solution : Tetramethylbenzydine (TMB).
  • Stop solution HCl 1M.


The minimum sensitivity detection limit of 25-hydroxyvitamin D, 25OH vitamin D, D2 and D3 (25OH-D2 and 25OH-D3) using current 25-OH vitamin D ELISA kit was approximately 2.81 ng/ml. The dynamic assay range for this assay is 5.0 – 120.0 ng/ml.


– 25-OH Vitamin D (25-Hydroxyvitamin D2/D3): ELISA
– Intra-Assay: 2.5 – 7.8%
– Inter-Assay: 4.3 – 9.2%
– Expected Values: Deficient <10 ng/ml, Insufficient 10-29 ng/ml, Sufficient 30-100 ng/ml, Potential Toxicity >100 ng/ml.
– Accuracy: Concentration 25 ng/ml (96 – 105%), Concentration 50 ng/ml (92 – 95%).


  1. Benefits and requirements of vitamin D for optimal health: a review. Altern Med Rev. (2005) 10 (2): 94-111. Grant WB, Holick MF.
  2. Development of a candidate reference measurement procedure for the determination of 25-hydroxyvitamin D3 and 25-hydroxyvitamin D2 in human serum using isotope-dilution liquid chromatography-tandem mass spectrometry. Anal Chem. (2010) 82 (5): 1942-8. Tai SS, Bedner M, Phinney KW.
  3. A candidate reference measurement procedure for quantifying serum concentrations of 25-hydroxyvitamin D₃ and 25- hydroxyvitamin D₂ using isotope-dilution liquid chromatography-tandem mass spectrometry. Anal Bioanal Chem. (2015) 407 (19): 5615-24. Mineva EM, et al.
  4. Blood biomarkers of vitamin D status. Am J Clin Nutr. (2008) 87 (4): 1087S-91S. Zerwekh JE.


  • Full Name: 25-OH Vitamin D ELISA Kit
  • Reactivity: Human
  • Sample Type: Serum
  • Sensitivity: 2.81 ng/ml



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