How is the ioPTH assay utilized in parathyroid surgery?
- The half-life of PTH is 3 to 5 minutes, allowing for a rapid assay for ioPTH to be used intraoperatively to assess the functional success of the operation.
- This test is performed by drawing a sample of blood before the operation and 10 minutes after the suspected abnormal glands have been removed. A reduction of the ioPTH by 50% predicts successful removal of all hyperfunctioning glands, and the surgery is terminated.
- The rate of multiglandular disease is approximately 5% to 15% when ioPTH is used to determine the completeness of resection, whereas the rate is 10% to 35% when conventional parathyroidectomy is performed (i.e., bilateral neck exploration and removal of grossly enlarged parathyroids).
- Therefore, the use of ioPTH may prevent the unnecessary removal of glands that appear enlarged but are not hyperfunctional.
