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25-OH Vitamin D

Vitamin D is converted to 25-hydroxyvitamin D (25-OH-VD) 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-VD 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-dihydroxy 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-VD can reflect the proper level of vitamin D in vivo.


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

Manufacturer

SEKBIO

Parameter

25-OH-VD Rapid Quantitative Test Kit (FIA)

Linearity

5~100ng/mL

Detection limit

5ng/mL

Benchmark product

Roche



Method Comparison

4.jpg



Sample

Roche

Sekbio

Sample

Roche

Sekbio

1

78.02

90.71

31

65.73

66.38

2

91.61

78.97

32

30.42

34.37

3

55.17

45.84

33

20.96

23.14

4

79.13

89.79

34

97.97

84.54

5

25.62

24.29

35

59.41

60.24

6

26.72

22.68

36

7.14

6.97

7

6.43

6.38

37

41.47

35.85

8

20.47

19.58

38

18.83

18.69

9

39.42

43.85

39

19.34

17.11

10

63.00

66.96

40

20.08

18.41

11

16.17

16.50

41

56.48

57.70

12

15.02

16.24

42

56.90

59.08

13

34.91

31.64

43

14.04

13.45

14

9.11

9.57

44

80.34

88.07

15

88.37

94.53

45

78.14

88.27

16

94.91

91.89

46

20.08

19.09

17

88.62

92.17

47

32.51

36.18

18

69.36

66.03

48

76.21

69.40

19

55.04

61.92

49

15.30

15.31

20

7.78

7.25

50

5.77

5.69

21

69.54

69.22

51

18.25

17.30

22

65.46

70.73

52

84.60

97.40

23

48.07

44.21

53

14.87

16.25

24

24.31

26.41

54

28.87

24.48

25

7.40

6.41

55

68.35

72.81

26

63.97

57.94

56

42.60

42.17

27

42.03

43.31

57

15.03

17.40

28

77.15

72.94

58

17.84

18.93

29

13.38

11.32

59

11.06

9.91

30

51.65

59.58

60

84.63

78.25


Linear

Cal

Concentration

Result

AVERAGE

S1

4.76

4.80

4.86

5.19

4.59

S2

14.78

15.75

14.98

13.18

16.01

S3

31.67

34.72

33.01

33.23

31.07

S4

60.84

62.68

60.91

58.22

61.83

S5

81.56

78.10

76.20

77.02

73.48

S6

103.58

109.51

113.18

123.39

106.63


3.jpg


 Accuracy

Cal

concentration

Result

Bias

A1

14.78

15.47

4.6%

15.58

5.4%

16.22

9.7%

A2

31.67

32.70

3.3%

29.35

-7.3%

29.57

-6.6%

A3

60.84

57.26

-5.9%

63.46

4.3%

63.46

4.3%


 Precision

Cal

Concentration

Cal

Concentration

Cal

Concentration

R1

14.19

R2

35.21

R3

59.28

14.04

27.37

61.50

16.50

30.93

54.36

15.71

32.58

61.36

15.22

30.98

52.39

16.90

28.45

68.70

13.10

36.27

63.53

15.57

31.41

54.62

14.81

27.06

62.28

13.54

34.88

57.39

AVE

14.96

AVE

31.51

AVE

59.54

SD

1.25

SD

3.26

SD

4.96

CV

8.4%

CV

10.4%

CV

8.3%



Vitamin D Products

AntibodyApplication
Sheep Anti-human 25-OH Vitamin D mAb

For immunodiagnostic: ELISA, LFA, CLIA

Mouse Anti-human 25-OH Vitamin D mAb
Humanized Anti-human 25-OH Vitamin D mAb


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-OH vitamin D in the serum consists of 25-OH vitamin D3, while 25-OH vitamin D2 becomes detectable only in individuals who supplement with vitamin D2.

Vitamin_D-binding_protein.jpg

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.

The_human_GC.jpg


Six point calibration test results







Conc.ng/ml

RLU

AVER

CV

S/N

0.00

1988864

1989951

1989408

0.04%

1.00

30.00

1701638

1717603

1709621

0.66%

1.16

75.00

1199394

1201402

1200398

0.12%

1.66

150.00

680993

677204

679099

0.39%

2.93

300.00

312820

318660

315740

1.31%

6.30

600.00

147914

146062

146988

0.89%

13.53 


Precision

Conc.ng/ml

Diluent Ratio

RLU

AVE

CV

Calculated Conc.

30.00

0.0

1701378

1678029

1682826

1687411

0.7%

32.52

144.00

0.2

705844

700950

722856

709883

1.6%

143.40

258.00

0.4

376481

382996

386917

382131

1.4%

254.55

372.00

0.6

249100

248073

255330

250834

1.6%

366.56

486.00

0.8

189357

191251

188225

189611

0.8%

470.47

600

1.0

147871

146779

150422

148357

1.3%

594.27 


Repeatability

Sample

RLU

C1

RLU

C2

Repeat 20 times

1221777

72.50

316434

299.72

1218254

72.84

316700

299.50

1199261

74.73

325984

292.12

1180962

76.59

324222

293.49

1193284

75.34

313327

302.28

1210626

73.60

315721

300.30

1186392

76.04

310303

304.83

1217894

72.88

328118

290.48

1192191

75.45

319156

297.51

1214137

73.25

320196

296.68

AVE

74.32

297.69

SD

1.48

4.57

CV≤8%

2.0%

1.5%


25-OH Vitamin D Intro

25-hydroxyvitamin D is the main form of vitamin D in the body. Vitamin D is a steroid derivative, is a fat-soluble vitamin, and is a cyclopentane poly hydro phenanthrene compound. Vitamin D is mainly synthesized by human skin after being irradiated by ultraviolet rays, and a small part is ingested from food or supplements. Vitamin D affects calcium and phosphorus metabolism and has a wide range of physiological effects. It is an indispensable substance for maintaining human health, cell growth, and development and is closely related to various diseases. There are two forms of vitamin D in the human body, vitamin D3 (cholecalciferol) and vitamin D2 (ergocalciferol), which are converted to 25-hydroxyvitamin D (25-OH-VD) by hydroxylation in the liver, which is then converted to active 1,25-dihydroxy vitamin D in the kidneys. The serum 25-OH-VD can reflect human vitamin D storage level, which is related to the clinical symptoms of vitamin D deficiency.

Vitamin D Antibody

Vitamin D is an important hormone that regulates calcium and phosphorus metabolism in the body. The skin mainly synthesizes it under sunlight conditions, and a small amount can obtain through diet. The active form of vitamin D is especially 1,25 dihydroxy vitamin D3 (1,25(OH) 2 D 3 ), which exerts physiological effects by binding to the vitamin D receptor (VDR). 25-hydroxyvitamin D (25(OH)D) is the body's primary storage form of vitamin D. 1,25(OH)D3 induces the differentiation of monocytes into macrophages and reduces the release of inflammatory cells and chemokines.

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