25-OH Hydroxy Vitamin D (Cholecalciferol D3) details
What 25-OH Hydroxy Vitamin D (Cholecalciferol D3) shows
25-Hydroxyvitamin D3 is the main circulating form of vitamin D3 (cholecalciferol), the type your skin makes in sunlight and that comes from foods like oily fish and from most supplements. Measuring D3 and D2 separately shows where your vitamin D is coming from, while the two together give your total 25-hydroxyvitamin D, the standard marker of vitamin D status. A low result can point to too little sun exposure, low intake or poor absorption, and very high levels usually reflect excess supplement use. Vitamin D supports calcium balance and bone health, and the result is usually read as part of the total and alongside calcium and, when relevant, parathyroid hormone.
Tests that include 25-OH Hydroxy Vitamin D (Cholecalciferol D3)
Vitamin D originating from dietary and endogenous sources is converted to 25-hydroxyvitamin D in the liver, and subsequently to 1, 25-dihydroxyvitamin D in the kidney. Measurement of both the 1, 25-Dihydroxy and 25-Hydroxy forms provide insights into a variety of medical conditions such Vitamin D status in renal failure, differential diagnosis of primary, secondary and tertiary hyperparathyroidism. Differential diagnosis of hypercalcemia and type I and II inherited rickets.
- Vitamin D, 25-OH, Total The combined measure of both major forms of vitamin D (D2 and D3) in your blood — the standard test used to assess overall vitamin D status.
- Calcitriol (1,25 di-OH Vitamin D) The active, hormone form of vitamin D that directly regulates calcium absorption. Tested less often than 25-OH vitamin D, mainly for kidney or calcium-regulation disorders.
- 25-OH Hydroxy Vitamin D (Cholecalciferol D3) The vitamin D3 portion of your 25-hydroxyvitamin D, coming from sunlight on your skin, animal foods and most supplements, used to assess vitamin D status.
- 25-OH Hydroxy Vitamin D (Ergocalciferol D2) The vitamin D2 portion of your 25-hydroxyvitamin D, which comes mainly from plant-based sources and prescription or some over-the-counter supplements.
- Vitamin D2, 1,25 (OH)2 Measures the active, hormone form of vitamin D made from vitamin D2, reported as part of a total 1,25-dihydroxyvitamin D (calcitriol) result.
- Vitamin D3, 1,25 (OH)2 Measures the active, hormone form of vitamin D made from vitamin D3, reported as part of a total 1,25-dihydroxyvitamin D (calcitriol) result.
QuestAssureD 25-Hydroxyvitamin D Test - This test measures the levels of Vitamin D in the body, which is crucial for bone health. It checks for Vitamin D activity, except in cases of renal disease. Low levels might indicate a dietary deficiency, poor absorption, or liver issues, leading to bone diseases like rickets and osteomalacia. High levels could cause hypercalcemia. The test specifically measures the two common forms of Vitamin D: 25-OH D3 and 25-OH D2.
- Vitamin D, 25-OH, Total The combined measure of both major forms of vitamin D (D2 and D3) in your blood — the standard test used to assess overall vitamin D status.
- 25-OH Hydroxy Vitamin D (Cholecalciferol D3) The vitamin D3 portion of your 25-hydroxyvitamin D, coming from sunlight on your skin, animal foods and most supplements, used to assess vitamin D status.
- 25-OH Hydroxy Vitamin D (Ergocalciferol D2) The vitamin D2 portion of your 25-hydroxyvitamin D, which comes mainly from plant-based sources and prescription or some over-the-counter supplements.
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