Vitamin D3, 1,25 (OH)2 details
What Vitamin D3, 1,25 (OH)2 shows
1,25-dihydroxyvitamin D3 is the active hormone form of vitamin D made from vitamin D3 (cholecalciferol), which your skin makes in sunlight and which also comes from foods and most supplements. The kidneys convert it to this active form, which helps control calcium and phosphate. It is reported alongside the D2 form to give total calcitriol. Higher levels can be seen with parathyroid overactivity or conditions such as sarcoidosis, and lower levels with kidney disease or some parathyroid problems. Calcitriol is tightly controlled and does not reflect your vitamin D stores, which are assessed with 25-hydroxyvitamin D, so it is interpreted with calcium and PTH.
Tests that include Vitamin D3, 1,25 (OH)2
This test checks the active form of vitamin D in your body. It's mainly used to help figure out why someone has low calcium levels and to keep an eye on people with bone problems due to kidney disease or those with chronic kidney failure. However, it's not the right test for finding out if you're low on vitamin D or for tracking how well vitamin D supplements are working. For those needs, the 25-hydroxyvitamin D test is recommended.
- 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.
- 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.
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.
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