Which tests measure 25-Hydroxyvitamin D3 (Cholecalciferol)?

25-Hydroxyvitamin D3 (Cholecalciferol) is measured in 1 test on BiomarkersLabs.com, including 25-Hydroxy Vitamin D (D2 + D3 Fractionated) Test.

Biomarker Reference · 25-OH-D3

What does the 25-Hydroxyvitamin D3 (Cholecalciferol) test measure?

Q: What is the reference range for 25-Hydroxyvitamin D3 (Cholecalciferol)?

The standard reference range for 25-Hydroxyvitamin D3 (Cholecalciferol) is Reported as the D3 fraction of total 25-OH-D; D3 is the dominant endogenous vitamer from cutaneous synthesis and most over-the-counter supplements.. Reference ranges vary by laboratory and assay platform — interpret in context of the issuing laboratory's stated range.

25-Hydroxyvitamin D3 (Cholecalciferol) (25-OH-D3) is a clinical biomarker used in vitamins-minerals assessment. 25-Hydroxyvitamin D3 is the 25-hydroxylation product of cholecalciferol, generated in the skin from 7-dehydrocholesterol under UV-B exposure and supplied by diet and most non-prescription supplements. It is measured in 1 laboratory test on BiomarkersLabs.com.

Reference Range: Reported as the D3 fraction of total 25-OH-D; D3 is the dominant endogenous vitamer from cutaneous synthesis and most over-the-counter supplements.
Units: ng/mL, nmol/L
Measured In: 1 test
Category: Vitamins & Minerals

Functional medicine optimalFunctional sufficiency is assessed on total 25-OH-D (commonly cited as 30–50 ng/mL), not on the D3 fraction alone.

What is 25-Hydroxyvitamin D3 (Cholecalciferol)?

25-Hydroxyvitamin D3 is the 25-hydroxylation product of cholecalciferol, generated in the skin from 7-dehydrocholesterol under UV-B exposure and supplied by diet and most non-prescription supplements. It is the principal circulating vitamer in people not taking D2, has a longer half-life (roughly two to three weeks) than D2, and is the fraction that best reflects cumulative endogenous and supplemental D3 status.

Why is 25-Hydroxyvitamin D3 (Cholecalciferol) measured?

The D3 fraction reflects sun exposure, dietary intake, and D3 supplementation. In a patient not on ergocalciferol it approximates the total, and a low D3 fraction despite an adequate total flags reliance on D2 dosing. Tracking the D3 fraction is useful where the source of repletion must be distinguished.

Reference ranges

Standard reference: Reported as the D3 fraction of total 25-OH-D; D3 is the dominant endogenous vitamer from cutaneous synthesis and most over-the-counter supplements.
Functional medicine optimal: Functional sufficiency is assessed on total 25-OH-D (commonly cited as 30–50 ng/mL), not on the D3 fraction alone.
Units: ng/mL, nmol/L

Reference ranges vary by laboratory and assay platform. Interpret in context of the issuing laboratory's stated range.

Tests that measure 25-Hydroxyvitamin D3 (Cholecalciferol)

1 test on BiomarkersLabs.com include this biomarker.

BML-VIT-021Comprehensive

25-Hydroxy Vitamin D (D2 + D3 Fractionated) Test

25-Hydroxyvitamin D3 (Cholecalciferol) reference range in this test: Reported as the D3 fraction of total 25-OH-D; D3 is the dominant endogenous vitamer from cutaneous synthesis and most over-the-counter supplements.

Related clinical conditions

Related Biomarkers

Frequently measured alongside

25-Hydroxyvitamin D2 (Ergocalciferol)25-OH-D21 test

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