Calcifediol (INN), also known as calcidiol , 25-hydroxycholecalciferol , or 25-hydroxyvitamin D (abbreviated < b> 25 (OH) D ), is a prehormone produced in the liver by hydroxylation of vitamin D 3 (cholecalciferol) by cholecalciferol 25-hydroxylase enzyme isolated by Michael F. Holick. Doctors around the world measure this metabolite to determine the patient's vitamin D status. At the daily intake of vitamin D3, full conversion to calcifediol takes about 7 days.
Calcifediol is then converted in the kidney (by enzyme 25 (OH) D-1? -hydroxylase) to calcitriol (1,25- (OH) 2 D 3 ), steroid hormone which is an active form of vitamin D. It can also be converted into 24-hydroxycalcidiol in the kidney via 24-hydroxylation.
Video Calcifediol
Blood test
In medicine, a 25-hydroxy vitamin D (calcifediol) blood test is used to determine how much vitamin D is in the body. Blood concentration of calcifediol is considered the best indicator of vitamin D status.
This test can be used to diagnose vitamin D deficiency, and this is indicated in patients at high risk for vitamin D deficiency and when test results will be used as supporting evidence to initiate aggressive therapy. Patients with osteoporosis, chronic renal disease, malabsorption, obesity, and some other infections may be at high risk and thus have greater indications for this test. Although vitamin D deficiency is common in some populations including those living in higher latitudes or with limited exposure to sunlight, the 25 (OH) D test is not indicated for the entire population. Your doctor may advise a low-risk patient to take over the over-the-counter vitamin D for examination.
This is the most sensitive step, though experts have called for increased standardization and reproducibility in different laboratories. According to MedlinePlus, the normal range of calcifediol is 30.0 to 74.0 ng/mL. The normal range varies greatly depending on several factors, including age and geographic location. A broad reference range of 20-150 nmol/L (8-60Ã, ng/mL) has also been suggested, while other studies have defined levels below 80 nmol/L (32 ng/mL) as an indication of vitamin D deficiency.
US laboratories generally report levels of 25 (OH) D as ng/mL. Other countries often use nmol/L. Duplicate ng/mL with 2.5 to convert to nmol/L.
Clinical interests
Increased levels of calcifedol are associated with increased calcium fractional uptake from the intestine up to the level of 80 nmol/L (32 ng/mL). Urinary calcium excretion balances calcium intestinal absorption and does not increase with calcifediol levels up to ~ 400 nmol/L (160 ng/mL).
A study by Cedric F. Garland and Frank C. Garland from the University of California, San Diego analyzed the blood of 25,000 volunteers from Washington County, Maryland, found that those with the highest levels of calcifediol had a risk of colon cancer that was one of them. -five of the usual fare. However, randomized controlled trials failed to find a significant correlation between low dose vitamin supplementation (400iu/day) and colon cancer risk.
A 2012 registry study of the Copenhagen, Danish population found a correlation between low serum and high serum levels and increased mortality, with levels of 50-60 nmol/L being associated with the lowest deaths. This study does not show cause-and-effect.
Maps Calcifediol
Interactive path map
Click on the genes, proteins and metabolites below to link to each article.
See also
- Hypervitaminosis D
- Hypovitaminosis D
- Vitamin D
- The health effects of Vitamin D
References
Source of the article : Wikipedia
0 Comments