Blood contamination in cerebrospinal fluid and its effect on biogenic amines and vitamins

Cerebrospinal fluid (CSF) analysis offers the most innocuous analytical tool for assessing the cellular and biochemical environment of CNS and hence aids in studying neurometabolomic conditions. The aim of this study was to assess the effect of blood contamination of CSF on the levels of selected biogenic amines and vitamins. CSF samples were spiked with increasing volumes of whole fresh blood (2.5%, 5%, 10% and 20%) under conditions: (a) spiking of pooled CSF samples followed by freezing to cause red blood cell (RBC) lysis; (b) spiking of pooled CSF samples followed by centrifugation to remove RBCs. CSF concentrations of two biogenic amines Homovanillic acid (HVA) and 5-hydroxyindoleaceticacid (5-HIAA); and three vitamins Pyridoxal 5’-phosphate (PLP),5-methyltetrahydrofolate (MTHF) and Thiamine were analysed by HPLC coupled with electrochemical detection. HVA and 5-HIAA illustrated lower values when RBC lysis was caused. However, PLP, 5-MTHF, and thiamine depicted higher concentrations on RBC lysis in contrast to RBC removal. CSF metabolomic investigations involving biogenic amines and vitamins as biomarkers is possible even when remarkable RBC CSF contamination occurs provided that CSF is centrifuged for the removal of RBC prior to freezing.