During parathyroid exploration for primary hyperparathyroidism, the surgeon uses intraoperative PTH monitoring (Miami criterion). A 50% decline in PTH is measured from the pre-excision level at 10 minutes post-excision, with the post-excision value being 32 pg/mL. The result is interpreted as:

• A Inconclusive — a 50% drop must also result in a value within the normal range
• B Failure — the PTH must fall below 20 pg/mL
• C Successful only if the pre-excision level was above 100 pg/mL
• D Successful — the Miami criterion is met and the operation can be concluded ✓

Explanation

The Miami criterion for successful parathyroidectomy requires only a ≥50% drop in intraoperative PTH from the highest pre-excision value at 10 minutes after excision, regardless of the absolute post-excision value. This criterion does not mandate that PTH fall within the normal range (10–65 pg/mL), distinguishing it from more stringent criteria used in some centres. A value of 32 pg/mL with a 50% decline meets the Miami criterion and confirms curative resection. Only a failure to achieve the 50% drop prompts further exploration.

Reference: Bailey & Love's Short Practice of Surgery, 27th ed.

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Written and medically reviewed by the StethoPrep medical team.