Vitamin B6 in plasma – sample stability and the reference limits

Abstract

Quantitatively, the most important B6 vitamer in plasma is pyridoxal-5′-phosphate (p-PLP). The prerequisite for the use of p-PLP measurements in patients with poor nutritional status is an appropriate reference interval, together with knowledge of the stability of vitamin B6 in plasma samples. We used blood samples from healthy blood donors to derive the reference limits for p-PLP, and to examine its stability for 24 hours at room temperature and at 4–8°C. P-PLP was measured using high performance liquid chromatography (HPLC). The reference interval in adults was 23–223 nmol/L. P-PLP was stable for 24 h at room temperature and at 4–8°C, allowing time for normal specimen transport.

Key Words::

• Chromatography
• high pressure liquid
• humans
• pyridoxal 5 phosphate
• reference range
• sample stability
• vitamin B6

Declaration of interest: The authors report no conflict of interest. The authors alone are responsible for the content and writing of the article.