Vitamin B1 (Thiamine)

The Vitamin B1 (thiamine) test is used to assess thiamine deficiency in symptomatic individuals and in those at increased risk because of insufficient intake, alcoholism, malabsorption disorders (including celiac disease), dependence on total parenteral nutrition, or prior bariatric procedures. Results aid the evaluation of deficiency‑related syndromes such as dry beriberi (peripheral neuropathy), wet beriberi with high‑output heart failure, and Wernicke–Korsakoff syndrome. The assay can also be used to track nutritional status in the setting of chronic disease. For search continuity, thiamine may be referred to as vitamin B1, aneurin, or the active coenzyme form thiamine diphosphate (TDP).

B‑complex vitamins are required in small quantities to sustain energy metabolism and normal tissue function. Thiamine serves as a coenzyme in glucose and amino acid metabolism and is necessary for the proper function of the nervous system, heart, and skeletal muscle. Common dietary sources include fortified grains and cereals, bran‑containing breads, potatoes, pork, seafood, nuts, and legumes. Deficiency can be evaluated by direct measurement of blood thiamine or by functional testing, and clinical outcomes of severe deficiency include wet beriberi with cardiac failure, dry beriberi manifesting as peripheral neuropathy, and Wernicke–Korsakoff syndrome. Because water‑soluble vitamins are stored in limited amounts, regular intake is required. Thiamine deficiency arises from inadequate consumption, impaired absorption or utilization, interference from other dietary factors, or increased physiologic needs. Groups at higher risk include those with malnutrition, chronic alcoholism, malabsorption (eg, celiac disease), individuals after bariatric surgery, older adults, and people with chronic illnesses; deficiency may also occur in pregnancy with restricted intake and in rare inborn errors of metabolism.