Equimolar Vitamin D measurement
Vitamin D is a fat soluble steroid hormone that occurs in two
forms, vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol).
Vitamin D enters the body through skin exposure to the sun or through
dietary intake, enters the circulation and is hydroxylated in the liver
to form 25(OH) Vitamin D. It is further hydroxylated in the kidney to
form the biologically active hormone, 1,25(OH) Vitamin D. The active
hormone is involved in the intestinal absorption of calcium and
phosphorous and interacts with the parathyroid gland (and its active
hormone called PTH Parathyroid Hormone) to act as a regulator of bone
formation. Vitamin D metabolites are bound to a vitamin D binding
protein in the plasma and are distributed throughout the body. Because
the concentration of 1,25(OH) Vitamin D is 1000 times lower than 25(OH)
Vitamin D and has a 4 hour half life, plasma 25(OH) Vitamin D is the
most reliable clinical indicator of vitamin D status. 25(OH) Vitamin D
levels are also indicative of the body’s storage levels of vitamin D and
correlate with the clinical symptoms of vitamin D deficiency. In the
late 18th century, Vitamin D was first recognized as an essential
dietary component in prevention of rickets. Recently, research has
indicated that vitamin D deficiency may be linked to chronic diseases
such as cancer (breast, colon and prostate), cardiovascular disease,
osteoporosis, osteomalacia and several autoimmune diseases. An assay for
total vitamin D (25-hydroxyvitamin D) with a measuring range up to 350
ng/mL on the VITROS® ECi/ECiQ Immunodiagnostic System is available at
Dr.Chhabra’s Pathology Centre. This combines good analytical and
clinical performance with the
operational simplicity of a rapid automated continuous random access
immunoassay system. The technology ensures that both Vitamin D2 and D3
fractions are measured so that a true picture is presented while
measuring baseline levels or while measuring post specific vitamin D
replacement therapy