Comparison of 'intraoperative' parathormone measurement with frozen section during parathyroid surgery

Intact parathyroid hormone (PTHi) has a relatively short half-life and levels fall significantly within 15 min of the successful excision of all the abnormal parathyroid glands during surgery for hyperparathyroidism. Monitoring this fall has been suggested as useful in decreasing the failure rate of neck explorations in parathyroid surgery. We have performed a comparative study of the use, during surgery for primary hyperparathyroidism, of routine frozen section with the recently available rapid assay for PTHi. The assay demonstrated a significant fall (P = 0.013) in the level of PTHi from a pre-excision mean of 26.66 pmol/l to 5.94 pmol/l 15 min after surgical excision. In all cases the level of PTHi fell to less than 30% of pre-excision levels by 30 min. However, while frozen section results were available in a mean time of 22 min after excision, the PTHi levels took a mean of 105 min. We conclude that during straightforward parathyroid surgery for primary hyperparathyroidism, the current assay does not offer any advantages over the already routine use of frozen section.