Question

In a patient operated for parathyroid adenoma, how do we confirm intraoperatively that the correct (culprit) gland has been removed?

• A. 50% reduction in PTH after 10 minutes
• B. 50% reduction in PTH after 5 minutes
• C. 25% reduction in PTH after 10 minutes
• D. 25% reduction in PTH after 5 minutes

Hint:

Recall the Miami criterion: how much PTH must fall, and at which minute mark?

Answer 1

The Correct Option is A

Step 1: PTH has a very short half-life (about 3 to 5 minutes), so removing the overactive gland causes a rapid fall in serum PTH. This is the basis of intraoperative PTH (IOPTH) monitoring.
Step 2: The widely used Miami criterion confirms successful excision when there is a >50% drop from the highest baseline IOPTH level measured at 10 minutes after the gland is removed.
Step 3: So the correct answer is a 50% reduction in PTH at 10 minutes. A 25% drop is too lax and would miss residual hyperfunctioning tissue; relying only on the 5-minute value is less reliable than the 10-minute mark in the standard Miami criterion.
Ref: Miami criterion (Carneiro et al., Surgery 2003) for intraoperative PTH monitoring.