Scottish Trace Element and Micronutrient Reference Laboratory

Scotland's specialised laboratory for trace elements and vitamins in health and disease

Vitamin B2

Trace Elements

Vitamins

Specialised services

The main circulating forms of Vitamin B2 are riboflavin and its two cofactors flavin adenine mononucleotide (FAM) and flavin dinucleotide (FAD). These two forms are detectable in both plasma and blood cells, however, the predominant form is FAD found in red blood cells. FDP and FAM act as coenzymes in oxidation-reduction reactions and in the respiratory chain (eg. cytochrome, glutathione reductase, glutathione peroxidase, and xanthine oxidase, methylene tetrahydrofolate reductase).

Specific vitamin B2 deficiency is very rare; it usually occurs in combination with another water soluble vitamin deficiencies, most commonly in alcoholics as a result of inadequate nutrition. Symptoms of deficiency are sore throat, inflammation of mouth tongue and throat, cracks in lips and corners of mouth, normocytic normochromic anaemia, and dermatitis. Vitamin B2 is essentially non-toxic.

Vitamin B2 is measured in red blood cells as flavin dinucleotide. Plasma vitamin B2 is bound to albumin and so concentrations fall during the acute phase response; this is not the case when vitamin B2 is measured in red blood cells.

Vitamin B2 is also measurable in whole blood which is less affected than plasma by acute phase response.

Sample Requirements and Reference Values