IDH1 and neoplasm: The D/L-2HG ratio was significantly higher in patients with an IDH1-mutated tumor compared to patients with an IDH1 wild-type tumor; 20.6 (95% confidence interval [CI] 8.6–32.5) versus 1.83 (95% CI 1.4–2.2; p < 0.0001; Figure 4).