BACKGROUND: The timing of intraoperative parathyroid hormone measurements during parathyroidectomy for the treatment of primary hyperparathyroidism is quite variable. Although a 50% decrease after excision is considered predictive of cure, it is not known which combination of measurements is most useful. METHODS: Two hundred thirteen patients underwent resection of solitary parathyroid adenomas. Sex, age, intraoperative parathyroid hormone level at baseline, before adenoma removal (T0), and 5 minutes (T5) and 10 minutes (T10) after adenoma removal; and 50% decrease were tested for associations with cure. RESULTS: A 50% decrease in intraoperative parathyroid hormone level was 95% sensitive for cure (95% confidence interval, 89% to 98%) but did not predict cure for individual patients. A decrease into the normal range was not correlated with cure (P > .50). However, a 50% decrease from T0 to T10 was 97% predictive of cure (odds ratio, 6.5; P = .08). CONCLUSIONS: The decrease in parathyroid hormone level from T0 to T10 during parathyroidectomy was most predictive of cure of primary hyperparathyroidism. A decrease into the normal range did not improve the performance characteristics of this test.
BACKGROUND: The timing of intraoperative parathyroid hormone measurements during parathyroidectomy for the treatment of primary hyperparathyroidism is quite variable. Although a 50% decrease after excision is considered predictive of cure, it is not known which combination of measurements is most useful. METHODS: Two hundred thirteen patients underwent resection of solitary parathyroid adenomas. Sex, age, intraoperative parathyroid hormone level at baseline, before adenoma removal (T0), and 5 minutes (T5) and 10 minutes (T10) after adenoma removal; and 50% decrease were tested for associations with cure. RESULTS: A 50% decrease in intraoperative parathyroid hormone level was 95% sensitive for cure (95% confidence interval, 89% to 98%) but did not predict cure for individual patients. A decrease into the normal range was not correlated with cure (P > .50). However, a 50% decrease from T0 to T10 was 97% predictive of cure (odds ratio, 6.5; P = .08). CONCLUSIONS: The decrease in parathyroid hormone level from T0 to T10 during parathyroidectomy was most predictive of cure of primary hyperparathyroidism. A decrease into the normal range did not improve the performance characteristics of this test.