Vitamin B6

VITAMIN B6 STATUS, red blood cell (Pyridoxal phosphate)
fE-ASATA(B6) ATK 7012

Pyridoxine vitamers (vitamin B6) form a group of substances with vitamin B6 activity. The group comprises free pyridoxine, pyridoxal and pyridoxamine. Pyridoxine is a water-soluble vitamin that acts as a coenzyme in the body in e.g. amino acid and carbohydrate metabolism.

Pyridoxal phosphate is the active form of vitamin B6.



Demonstrating pyridoxal phosphate deficiency.


Blood sample. Requires 12 hours of fasting. Glass of water and usual medication are allowed.

No vitamin B6 supplements during 12 hours. 


6 – 7 mL ACD or EDTA whole blood (12 h fasting).

Storage and delivery

Whole blood sample: Delivery at room temperature on sampling day. The sample must arrive within 24 hours (Mon-Fri). 

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 haemoglobin (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 B6 (pyridoxine)-dependent aspartate aminotransferase enzyme activity. 

Turnaround time

10 weekdays

Reference ranges

fE-ASATA(B6) 1.24 – 2.40


The notified value expresses the ratio of stimulated sample and zero sample. The further the ratio is from 1, the more the body is in need of vitamin B6.