M
0
[h=2]Introduction[/thanks]Vitamin D is essential for healthy bones and a deficiency in vitamin D can lead to a number of serious medical problems ranging from rickets and osteoporosis through to stroke, cancer and even depression. The circulating level of 25-hydroxy vitamin D [25(OH)D] is an important biomarker in the diagnosis of intestinal malabsorption and vitamin D deficiency or intoxication.
[h=2]Drawbacks in the Diagnosis of Vitamin D Deficiency[/thanks]New studies suggest that vitamin D deficiency is very common in the general population which has led to an exponential increase in the number of tests performed to check blood levels of 25(OH)D.
Vitamin D is biologically inert and its activation requires two successive hydroxylation reactions. The first hydroxylation takes place in the liver and gives 25(OH)D. The second reaction occurs mainly in the kidney and gives 1,25-dihydroxyvitamin D [1,25(OH)2D]. However, circulating 1,25(OH)2D is not a reliable indicator of vitamin D status, because the level often remains normal or elevated in cases of vitamin D deficiency.
The serum level of 25(OH)D is therefore used as an acceptable indicator of vitamin D status in clinical diagnosis. However, this form of vitamin D only has a half-life of four to six hours and is also carried in the circulation bound to a transport protein. A valid analytical technique is therefore required that dislodges 25(OH)D from this transport protein as well allowing a fast processing time.
A number of techniques exist for testing vitamin D status using the serum 25(OH)D level. Two forms of 25(OH)D contribute to an individuals
[h=2]Drawbacks in the Diagnosis of Vitamin D Deficiency[/thanks]New studies suggest that vitamin D deficiency is very common in the general population which has led to an exponential increase in the number of tests performed to check blood levels of 25(OH)D.
Vitamin D is biologically inert and its activation requires two successive hydroxylation reactions. The first hydroxylation takes place in the liver and gives 25(OH)D. The second reaction occurs mainly in the kidney and gives 1,25-dihydroxyvitamin D [1,25(OH)2D]. However, circulating 1,25(OH)2D is not a reliable indicator of vitamin D status, because the level often remains normal or elevated in cases of vitamin D deficiency.
The serum level of 25(OH)D is therefore used as an acceptable indicator of vitamin D status in clinical diagnosis. However, this form of vitamin D only has a half-life of four to six hours and is also carried in the circulation bound to a transport protein. A valid analytical technique is therefore required that dislodges 25(OH)D from this transport protein as well allowing a fast processing time.
A number of techniques exist for testing vitamin D status using the serum 25(OH)D level. Two forms of 25(OH)D contribute to an individuals