Li S, et al. - The risk factors of postoperative hyperkalemia were investigated in renal failure patients undergoing parathyroidectomy with autotransplantation (PTXa). In this work, age and preoperative serum potassium level were observed to have a significant negative correlation with postoperative serum potassium level. Correlation analysis and receiver operating characteristic curve method confirmed that use of the preoperative serum potassium level was the primary predictor of postoperative hyperkalemia. According to the Youden index of the receiver operating characteristic curve, the cutoff point for preoperative serum potassium level was 4.40 mmol/L.