For the determination of vitamin B6 a precipitation step to remove high molecular substances is performed first. After centrifugation the supernatant is mixed with a derivatisation solution and incubated for 20 min at 60°C. The fluorescent probe is then cooled (2-8°C), centrifuged and injected into the HPLC system. The isocratic separation via HPLC at 30°C lasts 10 minutes. The chromatograms are recorded by a fluorescence detector. The quantification is performed with the delivered plasma calibrator; the concentration is calculated via integration of the peak heights respectively areas. Sample Types: EDTA whole blood. Time: 30 minutes ? The vitamins pyridoxin, pyridoxal and pyridoxamin and the appropriate phosphate products are summarized as vitamin B6. All forms can be transformed into the active form pyridoxal-5-phosphate. Vitamin B6 functions as a coenzyme and is essential for more than 50 reactions in the protein, carbohydrate and fatty acid metabolism thereby synthesizing, transforming or degrading amino acids. In protein metabolism vitamin B6 supports the resorption of amino acids and their transport into the cells. Furthermore vitamin B6 contributes to the synthesis of neurotransmitters and amine products (histamine).