Vitamin B1

VITAMIN B1 STATUS, red blood cell (Thiamine)
fE-TKA(B1) ATK 8019

Thiamine, also known as vitamin B1, is a water-soluble vitamin that exists predominantly in the form of thiamine pyrophosphate (TPP) within the body. TPP functions as a coenzyme and plays a crucial role, particularly in carbohydrate metabolism. Reference:

Within the body, thiamine exists in various forms, including free thiamine and as mono-, di-, and triphosphate compounds. Thiamine diphosphate, a physiologically active form of vitamin B1, accounts for approximately 80% of the total thiamine content. Insufficient and unbalanced nutrition or malabsorption, triggered by factors like alcohol consumption, vomiting, or intestinal diseases, can lead to thiamine deficiency. Additionally, certain medications, particularly diuretics, have been identified to potentially provoke thiamine deficiency.


​Demonstrating thiamine deficiency. Thiamine deficiency may be indicated when neurological or psychiatric symptoms arise, raising suspicion of Wernicke’s disease. The risk groups for this condition include alcoholics, malnourished elderly individuals, those experiencing frequent vomiting, cancer patients, individuals susceptible to intestinal diseases, and those who receive parenteral nutrition.


Blood sample. Requires 12 hours of fasting. Glass of water and usual medication are allowed.
No vitamin B1 supplements during 12 hours.


6 – 7 mL Li-hep or EDTA whole blood (12 h fasting).

Mix the sample well. The tube must not contain any clots. 

Storage and delivery

Whole blood sample: Delivery at room temperature on sampling day. The sample must arrive within 24 hours (Mon-Fri). DO NOT FREEZE!

If the sample cannot be shipped on sampling day, it must be centrifuged, plasma removed and red blood cells washed with physiological saline. (Add a saline volume equivalent to the plasma volume into the tube, mix the sample and centrifuge. After centrifugation, remove the wash solution.)

Finally, the red blood cell mass must be diluted 1:1 with aqua. The dilution is divided into two tubes and it is tested for hemoglobin (B-vit Hb), which is written on the test requisition.

The processed sample can be stored refrigerated over the weekend. Delivery at room temperature if it arrives within 24 hours.


Enzymatic method that analyses vitamin B1 (thiamine)-dependent transketolase enzyme activity.

Reference ranges, calculated

fE-TKA(B1) 0.76 – 0.99

Turnaround time

10 weekdays

Interpretation of results

The provided figure represents the relationship between the blank sample and the stimulated sample. A larger deviation from 1 signifies a greater requirement for vitamin B1 within the body.

Baseline activity remains consistent even in the face of potential alterations in hemoglobin levels.


Last update 8.8.2023