During parathyroid surgery for adenoma, which statement about PTH values is not correct?

During parathyroid surgery for adenoma, which statement about PTH values is not correct?

• A. The second baseline value should be higher than the first baseline.
• B. The first baseline value should be the highest value of the three samples.
• C. The post-excision value should be at least 50% of or lower than the second baseline.
• D. The lack of decrease in the PTH value post-excision indicates possible multigland disease.

Answer: (B)

Intraoperative PTH monitoring relies on the hormone’s short half-life to confirm complete removal of the hyperfunctioning gland. Before excision, several PTH samples are taken to establish a baseline, and because PTH can fluctuate with stress or handling, the reference value used for judging success is the highest PTH value obtained among those pre-excision samples, not necessarily the first one drawn. After the adenoma is removed, PTH should fall quickly; a drop of about 50% or more from that highest baseline within roughly 10 minutes is considered evidence of cure. If the PTH does not decrease by that amount, multigland disease or additional hyperfunctioning tissue becomes a concern. The statement that is not correct is that the first baseline value should be the highest of the three samples. The correct approach uses the highest pre-excision value across the samples as the baseline, regardless of which sample happened to be drawn first. The other points align with the standard interpretation: post-excision PTH should drop by at least 50% from baseline, and failure to decrease suggests possible multigland disease.

Intraoperative PTH monitoring relies on the hormone’s short half-life to confirm complete removal of the hyperfunctioning gland. Before excision, several PTH samples are taken to establish a baseline, and because PTH can fluctuate with stress or handling, the reference value used for judging success is the highest PTH value obtained among those pre-excision samples, not necessarily the first one drawn. After the adenoma is removed, PTH should fall quickly; a drop of about 50% or more from that highest baseline within roughly 10 minutes is considered evidence of cure. If the PTH does not decrease by that amount, multigland disease or additional hyperfunctioning tissue becomes a concern.

The statement that is not correct is that the first baseline value should be the highest of the three samples. The correct approach uses the highest pre-excision value across the samples as the baseline, regardless of which sample happened to be drawn first. The other points align with the standard interpretation: post-excision PTH should drop by at least 50% from baseline, and failure to decrease suggests possible multigland disease.