A New Endpoint for Intraoperative PTH Measurement: Normal

Background: we hypothesized that io-pth levels would decline to normal or near normal after successful parathyroidectomy. objectives: to evaluate efficacy and predictive factor of parathyroid hormone measurement during parathyroid resection. materials and methods: every io-pth level from 2001-10 at a single institution was evaluated. charts were reviewed for preoperative diagnosis, final io-pth level, unilateral or bilateral exploration, calcium and parathyroid hormone levels. results: 225 patients underwent 594 io-pth measurements. 16 patients were excluded. final io-pth levels were normal (< 65 pg/ml) in 189 patients and elevated in 20 patients. 12 of 20 patients with elevated final io-pth levels had > 80% decrease, so that 201 patients had io-pth levels that were normal or dropped by > 80%. 8 patients had io-pth levels that dropped by < 80%, 4 of whom had < 50% decline. normal or near-normal io-pth level after resection of a parathyroid adenoma allowed unilateral exploration in 146 patients. persistent elevation of io-pth levels led to bilateral exploration in 22 patients. conclusions: io-pth levels should become normal or to drop by at least 80% during successful parathyroidectomy. persistent elevations of io-pth after resection of an abnormal gland dictates the need for bilateral exploration.