Our primary objectives were to compare detection rates across four clinically and methodologically relevant variables: biospecimen type, specifically CSF versus blood; CSF collection route, comparing lumbar puncture to cranial approaches such as subarachnoid, cisternal, or intraventricular sampling; the type of molecular assay, distinguishing targeted panels aimed at known alterations from broader, bespoke approaches, including differences in sequencing platforms such as next-generation sequencing or digital PCR; and IDH mutation status, comparing IDH-wildtype versus IDH-mutant gliomas. This evidence concerns the gene IDH1 and central nervous system cancer.