25-OH Vitamin D

Vitamin D is converted to 25 hydroxy d vitamin (25ohd vitamin d) by hydroxylation in the liver and the active 1, 25-dihydroxy vitamin D in the kidneys.

25 hydroxyvitamin D is the main form of vitamin D in the body.

The level of serum 25 oh d vitamin d can reflect the level of vitamin D storage and correlate with the clinical symptoms of vitamin D deficiency

Similar to other steroid hormones, 1, 25 oh vitamin d3 regulates tissue cell differentiation and related gene expression, mainly regulating blood calcium level and affecting cell differentiation.

25-OH-VD has a high content in blood and a long half-life.

It is stable and is not directly affected by diet and lifestyle. Therefore, clinical measurement of 25 oh vitamin d can reflect the proper level of vitamin D in vivo.

The performance date of 25-OH-VD Rapid Quantitative Test Kit (FIA)

Method Comparison

Linear

Accuracy

Precision

Vitamin D Products

VD product Introduction

Optimal Vitamin D status is determined by measuring the metabolite 25-OH vitamin D in the bloodstream. This form of vitamin D serves as the primary storage compound in the human body, significantly outweighing the biologically inactive circulating 1,25 (OH)2 vitamin D by approximately 1000-fold.

The circulating half-life of 25-OH vitamin D is approximately 2-3 weeks. It's worth noting that over 95% of measurable 25 0h vitamin d in the serum consists of 25-OH vitamin D3, while 25ohd2 becomes detectable only in individuals who supplement with vitamin D2.

Vitamin D-binding protein

The human GC is approximately 58 kDa in size and consists of 458 amino acids. Its genetic code is comprised of 1690 nucleotides located on chromosome 4 (4q11–q13). A notable feature of GC is its primary structure, which includes 28 cysteine residues forming multiple disulfide bonds. The protein is divided into three domains: domain 1 comprising 10 alpha helices, domain 2 consisting of 9 helices, and domain 3 with 4 helices.

Interestingly, the metabolism of these domains appears to differ, particularly in their interaction with vitamin D. Research indicates that the vitamin D binding protein, a component of GC, may exhibit a higher affinity for 25(OH)D3 (the metabolite of vitamin D3) compared to 25(OH)D2 (the metabolite of vitamin D2). This finding was observed in a specific study.