Persistently elevated parathyroid hormone after successful parathyroid surgery.

Objectives/hypothesis: Explore potential causes of persistently elevated parathyroid hormone levels after curative parathyroidectomy in patients with primary hyperparathyroidism due to single gland disease.

Study Design: Case series with planned data collection.

Methods: An analysis was undertaken of 314 patients with primary hyperparathyroidism undergoing parathyroid surgery in a tertiary academic practice between January 2009 and April 2013.