Holotranscobalamin versus Total Vitamin B12 as Indicators of Vitamin B12 deficiency in Thyrogastric Syndrome

The autoimmune association of Hashimoto thyroiditis and atrophic body gastritis (ABG) is known as thyrogastric syndrome which occurs in at least 14% of autoimmune thyroid disease (ATD). ABG is characterized by the loss of HCl and intrinsic factor (IF) production and is often underdiagnosed. It is important to make an early diagnosis because patients with ABG have greater risk for developing gastric cancer and ABG is responsible for anemia. Holotranscobalamin (HoloTC) is the biologically active form of vitamin B12 (cobalamin) and represents only around 20% of total vitamin B12. HoloTC is believed to be an earlier detection marker than total vitamin B12 to diagnose cobalamin deficiency which is especially frequent when gastritis manifestations are present.