25OH
25OH is a common abbreviation used in biochemistry and medicine to refer to 25-hydroxyvitamin D. This molecule is the primary circulating form of vitamin D in the blood and is produced in the liver from vitamin D by the enzyme 25-hydroxylase. 25-hydroxyvitamin D circulates in the bloodstream and is then converted in the kidneys to the biologically active form, 1,25-dihydroxyvitamin D, also known as calcitriol.
The measurement of 25OH levels in blood serum is the standard method for assessing a person's vitamin