Métabolisme calcique

Nom du produit

25-OH-Vitamin D direct (Quidel®)

Cat. no8046
Gamme5 - 130 ng/ml (12,5 – 325 nmol/l)
Sensibilité1,5 ng/ml (3,75 nmol/l)
Durée d'incubation3 hours
Volume échantillon50 µL
Echantillon

Serum

Précautions

Samples are stable for 24 hours at 2-8 °C.
Long-term storage at -20 °C or below.
Avoid repeated freeze/thaw cycles.

Valeurs de référence

Deficiency (seriously deficient)          < 10 ng/ml resp. < 25 nmol/l
Insufficiency (deficient)                     10 - 30 ng/ml resp. 25 - 75 nmol/l
Sufficiency (adequately supplied)     30 - 150 ng/ml resp. 75 - 375 nmol/l
Toxic                                                  > 150 ng/ml resp. 375 nmol/l

Espèces

Human

Spécificité

25-OH-Vitamin D3    100,0 %
25-OH-Vitamin D2     84 %

Vitamin D2 & D3        < 0,2 %

Intérêt clinique

Vitamin D is a steroid hormone involved in the intestinal absorption of calcium and the regulation of calcium homeostasis. There are two different forms of Vitamin D, named D3 and D2, which are very similar in structure. The Vitamin D2 is a synthetic product, which is predominantly absorbed by fortified food.
Physiological Vitamin D3 levels result not only from dietary uptake but can also be produced from a cholesterol precursor, 7-dehydrocholesterol, in the skin during sun exposure. In the liver, the vitamin is hydroxylated to 25-hydroxyvitamin D (25-OH-Vitamin D), the major circulating metabolite of Vitamin D. Although 1,25-(OH)2 Vitamin D portrays the biological active form of Vitamin D, which is synthesized in the kidney, it is widely accepted that the measurement of circulating 25-OH-Vitamin D provides better information with respect to patients Vitamin D status and allows its use in diagnose hypovitaminosis.
The concentration of 25-OH-Vitamin D decreases with age and a deficiency is common among elderly persons.
Clinical applications of 25-OH-Vitamin D measurements are the diagnosis and therapy control of postmenopausal osteoporosis, rickets, osteomalacia, renal osteodystrophy, pregnancy, neonatal hypocalcemia and hyperparathyroidism. In addition, a prevalence of subclinical Vitamin D deficiency has been discussed in different European countries.
Vitamin D intoxication mostly occurs during a large intake of pharmaceutical preparations of Vitamin D and may lead to hypercalcemia, hypercalcuria and nephrocalcinosis in susceptible infants.

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