INTENDED USE

The Vitamin D Semi-Quantitative Rapid Test Device (Whole Blood/Serum/Plasma) is used for semi-quantitative determination and monitoring of 25-OH Vitamin D concentrations in whole blood/serum/plasma specimens.

SUMMARY

Vitamin D is a group of fat-soluble secosteroids responsible for increasing intestinal absorption of calcium, magnesium, and phosphate, and for many other biological effects. In humans, the most important compounds in this group are vitamin D3 (cholecalciferol) and vitamin D2 (ergocalciferol).
The major natural source of vitamin D is synthesis of cholecalciferol in the lower layers of the epidermis of the skin, through a photochemical reaction of UVB light, from the sun exposure (specifically UVB radiation) or UVB lamps. Cholecalciferol and ergocalciferol can be ingested from the diet and supplements. Only a few foods, such as the flesh of fatty fish, naturally contain significant amounts of vitamin D. Dietary recommendations typically assume that all of a person’s vitamin D is taken by mouth, because sun exposure in the population is variable and recommendations about the amount of sun exposure that is safe are uncertain in view of the skin cancer risk.
Vitamin D from the diet, or from skin synthesis, is biologically inactive. It is activated by two protein enzyme hydroxylation steps, the first in the liver and the second in the kidneys. Because vitamin D can be synthesized in adequate amounts by most mammals if they get enough sunlight, it is not essential and therefore is technically not a vitamin. Instead it can be considered a hormone, with activation of the vitamin D pro-hormone resulting in the active form, calcitriol, which then produces effects via a nuclear receptor in multiple locations.
The Vitamin D Semi-Quantitative Rapid Test Device (Whole Blood/Serum/Plasma) is an immunochromatographic test, based on two specific antibodies against 25-OH Vitamin D. The concentration-dependent formation of test lines allows a rapid semiquantitative determination of 25-OH Vitamin D in whole blood /Serum/Plasma samples.

PRINCIPLE

The test sample which is diluted with buffer solution add to the sample well of the test device. The sample now moves through the test strip from bottom to top. If the test sample contains 25-OH Vitamin D, it attaches to the first anti-25-OH Vitamin D antibody which is conjugated with a red gold colloidal for color marking. The red 25-OH Vitamin D antibody-gold complex, together with the sample liquid, diffuses through the membrane that is pre dispensed with lines of different amounts of the second anti-25-OH Vitamin D antibody. The 25-OH Vitamin D-antibody-gold complex is immobilized by the antibodies coated on the membrane leading to the formation of red lines. The number of lines depends on the 25-OH Vitamin D concentration in the sample.
The control line serves as a procedural control and indicates that sufficient volume of specimen has been added and membrane wicking has occurred.