Overall, sensitivity for detection of the “astrocytoma, IDH mutant, high grade” methylation class by a LINE-1 methylation level of ≤77% was 94.7% (95% CI 74.0–99.9%) and specificity was 90.2% (95% CI 79.8–96.3%). The gene discussed is IDH2; the disease is astrocytoma (excluding glioblastoma).