Active vitamin B12 (holotranscobalamin) | Laboratory research

General Information

For the early detection of vitamin B12 deficiency, it is important to examine the indicator of its active form - holotranscobalamin.

Vitamin B12 plays an important role in the synthesis of red blood cells - erythrocytes and DNA, in the proper functioning of nerve fibers and in maintaining cognitive abilities. Vitamin B12 circulating in plasma is bound to two proteins - transcobalamin and haptocorin. Almost a quarter of circulating cobalamin (vitamin B12) is bound to transcobalamin and delivered to cells and tissues in this form. The complex of the protein transcobalamin and vitamin B12 is called holotranscobalamin, and it is the biologically active part of the vitamin. The remaining 12% of vitamin B80 is biologically inactive and is transported by the protein haptocorin. Receptors for the haptocorin and vitamin B12 complex are not present in cell membranes, except for liver cells.

Vitamin B12 deficiency develops when it is not taken with food, or when it is not absorbed from the intestine (pernicious anemia).

Without timely diagnostics, vitamin B12 deficiency causes anemia, damage to nerve fibers, disruption of thinking and memory functions.

Low serum concentrations of vitamin B12 are more common in the elderly, HIV-infected, and vegans. The bodies of pregnant women and nursing mothers require a relatively large dose of vitamin B12.

Holotranscobalamin is an early biomarker of vitamin B12 deficiency. It is a more sensitive marker than the total vitamin B12 threshold to assess deficiency.

When is the survey conducted?

• Diagnosis and monitoring of pernicious anemia
• Evaluation of blood B12 levels in vegetarians and vegans
• Disorders of the gastrointestinal tract (Crohn's disease, gastritis caused by Helicobacter pylori, gastric ulcer, etc.)
• Monitoring the condition after gastric resection

Study sample:Venous blood

Reference boundaries25.1 – 165 picomoles/liter

Interpretation of results

The concentration of holotranscobalamin is lower in women than in men, and with increasing age the rate decreases even more.