UNLABELLED: Biochemical analyses of cerebrospinal fluid (CSF) are routinely performed at diagnosis in many pediatric oncology and hematology centers when acute leukemia is diagnosed. However, the clinical relevance of these analyses remains unclear. We conducted a retrospective analysis of biochemical CSF data from children diagnosed with acute leukemia at two French hospitals between 2016 and 2023 assessing the results in relation to the presence or absence of leukemic neuromeningeal involvement and the correlation between cytological and biochemical analyses. On 151 patients, 13 had a central nervous involvement (CNS), only one with neurological symptoms. All our patients had a biochemical analysis of CSF at diagnosis. We did not find any strong correlation (p <
0.05) between cytological studies and biochemical analysis in CSF. CONCLUSION: Without therapeutic impact, we conclude that routine measurement of biochemical analysis in the CSF is not indicated in children with acute leukemia. WHAT IS KNOWN: • Biochemical analysis of the cerebrospinal fluid (CSF) is routinely performed in children with acute leukemia in some centers while its clinical value remains uncertain. • Cytology is the gold standard technique for the detection of central nervous system (CNS) involvement in leukemia. WHAT IS NEW: • No significant correlation was found between CSF biochemical and cytological analyses and CSF biochemical analysis had no added clinical value in this study. • Our results suggest that routine CSF biochemical analysis may be omitted in this clinical context.