Based on the screening criterion of AUC values ≥ 0.95, four genes (ADH1B, ABR, SERPINA1, and LPAR5) in both the GSE33630 and GSE138198 datasets were identified as common key genes in HT and PTC (Supplementary Table 10; Figures 6A–C), and the Youden’s index for each key gene was calculated in Figure S1. The gene discussed is ADH1B; the disease is hematocrit.