Perioperative parathyroid hormone assay for diagnosis and management of postthyroidectomy hypocalcemia

Objectives/Hypothesis: The purpose of this study was to assess the relationship between perioperative changes in parathyroid hormone (PTH) level and the likelihood of postthyroidectomy hypocalcemia. Study Design: In a series of 78 patients undergoing total or completion thyroidectomy, PTH levels were measured before surgery and at 10 minutes after removal of the thyroid gland. Methods: A prospective, nonrandomized collection of serum from 78 consecutive total or completion thyroidectomy procedures performed by a single surgeon was carried out over 18 months. Analysis is made of PTH levels, serum calcium values, need for calcium supplementation, and symptoms of hypocalcemia. Results. Both a PTH change of 75% and an absolute postoperative PTH of 7 pg/mL are accurate standards for predicting symptomatic hypocalcemia after total or completion thyroid surgery. Conclusions. Perioperative PTH levels are a tool for the prediction of postoperative symptomatic hypocalcemia after thyroidectomy. A PTH level drawn 10 minutes after removal of the thyroid predicts the likelihood of postoperative hypocalcemia. Key Words. Hypocalcemia, parathormone assay, PTH, total thyroidectomy, completion thyroidectomy.