Biologically active vitamin B1 (thiamine) is a test based on a microbiological method that measures the total biologically active vitamin B1 content in a blood sample.
What are the benefits of measuring Biologically Active Vitamins?
This test measures the biologically active in vivo metabolites of B vitamins. Vitamins' biological action (bioactivity) has greater value and is a more representative indication of their active concentration than the simple chemical measurement of their levels, especially in cases where these indications are used to determine substitution therapy or to check a therapeutic intervention.
Measurement of biologically active vitamins is recommended when the examination of vitamins in plasma, serum, or whole blood is in the gray zone, i.e., have borderline values, and when the measured levels of vitamins are incompatible with the observed clinical picture or other laboratory tests.
The bioactive form of vitamin B1 is thiamin pyrophosphate. It plays a vital role as a co-enzyme in carbohydrate and amino acid metabolism. Thiamine pyrophosphate is an essential co-factor for enzymes involved in several key metabolic processes in the nervous system, the heart, the blood cells, and the muscle. Vitamin B1 assists in the conversion of carbohydrates into energy, which is necessary for healthy brain and nerve cells and heart function.
Vitamin B1 deficiency
Vitamin B1 deficiency may result from a deficiency in the diet. Eventually, a severe vitamin B1 deficiency may lead to Beriberi, characterized by nerve, heart, and brain abnormalities. Deficiency may occur in alcoholics or in particular clinical situations such as hemodialysis, chronic peritoneal dialysis, or after administration of glucose to a vitamin B1-depleted patient. Further vitamin B1 deficiency diseases are Wernicke‘s encephalopathy, Korsakow syndrome, and some forms of Landry‘s paralysis. Myopathy also was found in relation to thiamine deficiency.
Indications for vitamin B1 determination
- Suspicion of vitamin B1 deficiency
- Determination of the metabolically active vitamin B1
- Vitamin B1 supplementation of patients receiving total parenteral nutrition
- Disorders of the amino acid metabolism
- Malabsorption due to alcoholism
- Patients with suspected neuritis
How are Biologically Active Vitamins measured?
To test the biologically active vitamins, the blood sample is subjected to an enzymatic pre-treatment and then placed in microplates containing microorganisms sensitive to these vitamins (e.g., Lactobacillus fermentum, Lactobacillus rhamnosus, Lactobacillus leichmanii, Saccharomyces cerevisiae). The nutrient medium, specific and unique to each vitamin, contains all the necessary ingredients for the growth of microorganisms, except for the vitamin to be measured. When the patient's blood is added to the material, the microorganisms grow until the examined vitamin is depleted. The growth of microorganisms is measured after 72 hours of incubation in a particular multi-channel analyzer and compared to standard concentrations of vitamins. The bioactivity of the tested vitamin is directly proportional to the measured growth of microorganisms.
