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- Serum 1,25 (OH) 2 D provides no information about vitamin D status and is often normal or even elevated due to secondary hyperparathyroidism associated with vitamin D deficiency. Most experts agree that 25 (OH)D of < 20 ng/ml is considered to be vitamin D deficiency whereas a 25 (OH)D of 21-29 ng/ml is considered to be insufficient.
People also ask
What factors affect 25-hydroxyvitamin D concentration in response to vitamin D supplementation?
Does vitamin D affect 25(OH)D concentration?
What factors affect a 25 (OH)D response to vitamin D?
Jun 25, 2015 · Vitamin D supplementation is currently the best approach to treat deficiency and to maintain adequacy. In response to a given dose of vitamin D, the effect on 25 (OH)D concentration differs between individuals, and it is imperative that factors affecting this response be identified.
- Hajar Mazahery, Pamela R. von Hurst
- 2015
- Overview
- Why is a 25-hydroxy vitamin D test done?
- How is the 25-hydroxy vitamin D test performed?
- Evaluating the results of a 25-hydroxy vitamin D test
- Risks of a 25-hydroxy vitamin D test
- Outlook
Doctors use the 25-hydroxy vitamin D test to monitor your vitamin D levels. Low levels can mean you need to spend more time outdoors or adjust your diet. But it can also occur with certain medical conditions.
Vitamin D helps your body absorb calcium and maintain strong bones throughout your entire life. Your body produces vitamin D when the sun’s UV rays contact your skin. Other good sources of the vitamin include fish, eggs, and fortified dairy products. It’s also available as a dietary supplement.
Vitamin D must go through several processes in your body before your body can use it. The first transformation occurs in the liver. Here, your body converts vitamin D to a chemical known as 25-hydroxyvitamin D, also called calcidiol.
The 25-hydroxy vitamin D test is the best way to monitor vitamin D levels. The amount of 25-hydroxyvitamin D in your blood is a good indication of how much vitamin D your body has. The test can determine if your vitamin D levels are too high or too low.
Your doctor may request a 25-hydroxy vitamin D test for several different reasons. It can help them figure out whether too much or too little vitamin D is causing bone weakness or other abnormalities. It can also monitor people who are at risk for having a vitamin D deficiency.
Those who are at high risk of having low levels of vitamin D include:
•people who don’t get much exposure to the sun
•older adults
•people with obesity
•babies who are breastfed only (formula is usually fortified with vitamin D)
Your doctor will tell you not to eat anything for four to eight hours before the test.
The 25-hydroxy vitamin D test requires a common blood test. Your healthcare provider will draw blood from a vein in your arm using a needle. A quick finger prick will more than likely provide enough for a blood sample in children and infants.
Results will depend on your age, sex, and the testing methods used. Results can also slightly vary from lab to lab.
According to the Office of Dietary Supplements (ODS), levels of vitamin D are measured by the 25-hydroxy level in nanomoles/liter (nmol/L) or nanograms/milliliter (ng/mL). The results can indicate the following:
•deficiency: less than 30 nmol/L (12 ng/mL)
•potential deficiency: between 30 nmol/L (12 ng/mL) and 50 nmol/L (20 ng/mL)
•normal levels: between 50 nmol/L (20 ng/mL) and 125 nmol/L (50 ng/mL)
•high levels: higher than 125 nmol/L (50 ng/mL)
As with any routine blood test, risks of the 25-hydroxy vitamin test are minimal and include:
•excessive bleeding
•lightheadedness
•a slight chance of infection where the needle pierces your skin
Vitamin D is vital to the body. Deficiencies at any age can cause problems. Your doctor may recommend supplements or other treatment options if you’re very deficient. Eating foods that contain vitamin D in addition to adding supplements to your regimen can help keep your vitamin D levels stable.
Jun 25, 2015 · Circulating 25(OH)D is currently considered the best determinant of vitamin D status compared to other vitamin D metabolites namely vitamin D and 1,25(OH) 2 D because: (1) its half-life is much longer, though the definite time is controversial (ranging from three weeks to three months) [29,30]; (2) its production in the liver is not ...
- Hajar Mazahery, Pamela R. von Hurst
- 2015
Serum 1,25 (OH) 2 D provides no information about vitamin D status and is often normal or even elevated due to secondary hyperparathyroidism associated with vitamin D deficiency. Most experts agree that 25 (OH)D of < 20 ng/ml is considered to be vitamin D deficiency whereas a 25 (OH)D of 21-29 ng/ml is considered to be insufficient.
- Michael F. Holick
- 10.1016/j.annepidem.2007.12.001
- 2009
- 2009/02
In a summary of 13 studies carried out during the period 1977–1996, the increase in 25(OH)D varied from 1.47–8.75 nmol/L (0.59–3.5 ng/mL) per 100 IU (2.5 μg) of oral vitamin D intake. 38 In subjects with an average 25(OH)D concentration of 47 nmol/L (18.8 ng/mL), treatment with vitamin D at concentrations of 1000 IU/d (25 μg/d) or 4000 ...
- Indra Ramasamy
- 10.33176/AACB-20-00006
- 2020
- Clin Biochem Rev. 2020 Dec; 41(3): 103-126.
Except in those with conditions causing hypersensitivity, there is no evidence of adverse effects with serum 25 (OH)D concentrations <140 nmol/L, which require a total vitamin D supply of 250 μg (10000 IU)/d to attain.
Jan 29, 2020 · Measuring 25 (OH)D concentrations is one way to both increase the awareness of vitamin D’s importance in maintaining good health and to encourage vitamin D supplementation or increased...
