Košec A, et al. - Researchers conducted this prospective, single-center, non-randomized longitudinal cohort study to assess the value of serum calcium and parathyroid hormone (PTH) concentration measurements after total thyroidectomy in anticipatng late-occurring hypocalcemia, defined as serum calcium levels < 2.14 mmol/L regardless of clinical symptoms. The sample consisted of 143 individuals undergoing thyroidectomy between August 2019 and December 2019 with serum calcium and PTH levels sampled 1 h after surgery and on the first and fifth postoperative day. Data reported that 52 patients had hypocalcemia on the fifth postoperative day. Findings suggested an association of advanced age, concomitant neck dissection and serum PTH levels < 2.9 pmol/L 1 h after surgery and on the first postoperative surgery day with a high risk of hypocalcemia on the first and fifth postoperative day and demand for higher doses of calcium supplements. A reliable predictor of postoperative hypocalcemia with important clinical implications is the serum PTH level assessed immediately after surgery and on the first postoperative day.