Introduction: Studying the amino acids in cerebrospinal fluid (CSF) is essential in the diagnosis of some neurological diseases and is an important aid in the diagnosis of others. No research has been published in the literature to prove the physiological relationship between the values of amino acids in CSF and plasma in the paediatric population.
Aim: To define a set of ratios for amino acids in plasma and CSF in the paediatric population that can be used in daily clinical practice.
Patients and methods: The aminograms in plasma and CSF of 105 patients with ages between 0 and 12 months were collected and analysed retrospectively. Aminograms with amino acid values that are considered to be normal according to the reference values of our laboratory were included in the sample. The quantitative analysis of amino acids was performed using high-resolution liquid chromatography and statistical analysis with the software application SPSS 19.0.
Results: The mean values, range and standard deviation of the amino acid concentrations in plasma and CSF, together with the CSF/plasma ratios, are reported. Significant correlations were found from 0.6 onwards between different neutral amino acids, above all in those with smaller molecular weights (Thr, Ser, Gly and Ala).
Conclusions: The existence of significant correlations between the different neutral amino acids supports the idea that they share the same transporters in the blood-brain barrier. Standardising the amino acid ratios will make it possible to increase sensitivity in the detection of pathological values in plasma and CSF, to further knowledge of the pathophysiology of neurological diseases and perhaps to describe new aminoacidopathies.