**7. Conclusions**

After successful TPX & BT plus AT for secondary hyperparathyroidism, severe hypocalcemia occurred in 23.3% of patients in our series. The risk factors for severe hypocalcemia were young age, low preoperative Ca levels, high preoperative Alk-ptase levels, and long operation time. Serum Ca levels <7.6 mg/dL at 18 h post-operation were the optimal cutoff value for hypocalcemia that needed i.v. Ca gluconate. When the suggested clinical algorithm was followed, the mean duration of post-operative hospital stay due to severe hypocalcemia was short (6.4 ± 2.5 days) and readmission rate (0.62%) due to hypocalcemia was quite low.
