Pyridoxal 5′-phosphate, pyridoxal, and 4-pyridoxic acid in the paired serum and cerebrospinal fluid of children

We quantified pyridoxal 5′-phosphate (PLP), pyridoxal (PL), and 4-pyridoxic acid (PA) in paired serum and cerebrospinal fluid (CSF) samples from children and investigated the effect of age on the concentrations and CSF-to-serum ratios of these vitamers. Serum and CSF samples prospectively collected from 49 pediatric patients were analyzed. PLP, PL, and PA were measured using high-performance liquid chromatography with fluorescence detection, using pre-column derivatization by semicarbazide. Effects of age on these vitamers, the PLP-to-PL ratio, CSF-to-serum PLP ratio, and CSF-to-serum PL ratio were evaluated using correlation analysis. The PLP, PL, and PA concentrations in the serum and CSF were higher at younger ages, except for CSF PA concentrations that were mostly below the limit of detection (