In this article we will be discussing a very common question: vitamin d 25 hydroxy d3 levels.
Reference Range
Many of the currently available assays measure and report on both vitamin D2 and D3 metabolites. 25-hydroxyvitamin D (25(OH)D) is the major circulating form of vitamin D; thus, the total serum 25(OH)D level is currently considered the best indicator of vitamin D supply to the body from cutaneous synthesis and nutritional intake. One exception is that 25(OH)D levels do not indicate clinical vitamin D status in patients with chronic renal failure or type 1 vitamin D-dependent rickets or when calcitriol (1,25-dihydroxyvitamin D) is used as a supplement.
Symptoms And Health Risks Of Vitamin D Deficiency
How The Test Is Performed
In D is measured as nanograms per milliliter (ng/mL). Others recommend a level between 30 and 50 ng/mL. Normal value ranges may vary slightly among different laboratories.
Talk to your doctor about the meaning of your specific test results, and whether you may need vitamin D supplements. Many people are confused by the way these tests are reporte.
Historical Perspective
The lack of adequate sun exposure resulted in an epidemic of children with severe growth retardation and bony deformities that was commonly known as rickets.1 In 1919, Huldschinsky et al2 reported that exposure to ultraviolet radiation cured rickets.
This was followed by Hess and Unger in 19213 who observed that exposure to sunlight cured rickets.