Verification in the CKD dataset GSE120683 showed that RSAD2 (AUC = 0.889, 95%CI = 0.5809–1), CXCL1 (AUC = 0.889, 95%CI = 0.5809–1), LRRK2 (AUC = 0.667, 95%CI = 0.1332–1), PPBP (AUC = 0.889, 95%CI = 0.5809–1), and RGS18 (AUC = 0.667, 95%CI = 0.1332–1), among which RSAD2, CXCL1, and PPBP had the same diagnostic value for CKD (Figure 6B). The gene discussed is PPBP; the disease is chronic kidney disease.