A prospective evaluation of the effect of sample collection site on intraoperative parathormone monitoring during parathyroidectomy.
BACKGROUND
Sample collection site may affect the dynamics of intraoperative parathyroid hormone monitoring (IPM) and influence surgical decisions.


METHODS
We prospectively studied 45 patients undergoing parathyroidectomy for primary hyperparathyroidism. The IPM cure criterion was a decrease in peripheral vein (PV) parathyroid hormone (PTH) of >50% at 10 minutes after gland excision. PTH samples were collected simultaneously from PV and central vein (CV) and compared for PTH decay, the incidence of >50% PTH decay, and the incidence of normal PTH values after gland excision.


RESULTS
Mean PTH levels were significantly higher from the CV before and after gland excision. Mean PTH decay 10 minutes after gland excision was 89% PV versus 88% CV, resulting in mean PTH levels of 27 +/- 23 and 39 +/- 35 pg/mL, respectively (P < .0001). At 5 minutes, >50% decay in PTH was present in 98% PV versus 88% CV samples. By 10 minutes, the incidence of >50% PTH decay was equivalent (98%). This yielded normal range PTH levels from the PV versus CV in 90% versus 76% of patients at 5 minutes, 96% versus 89% at 10 minutes, and 95% versus 81% at 20 minutes. Of 45 patients, 44 (98%) are normocalcemic at a mean follow-up of 6.3 months. IPM predicted the single operative failure.


CONCLUSIONS
CV sampling produces significantly higher PTH levels. Surgeons sampling from a PV may observe a >50% decrease in PTH and normal range PTH values starting 5 minutes after gland excision. Surgeons who sample from the CV and require normalization of PTH levels may have to wait longer and/or continue potentially unnecessary neck exploration.
Beyer
Todd D
TD
Albany Medical College, Albany, NY 12208, USA. beyert@mail.amc.edu
Chen
Emery
E
Ata
Ashar
A
DeCresce
Robert
R
Prinz
Richard A
RA
Solorzano
Carmen C
CC
D000328:Adult; D000368:Aged; D001800:Blood Specimen Collection / Q000379:methods*; D005069:Evaluation Studies as Topic; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D049950:Hyperparathyroidism, Primary / Q000175:diagnosis / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D019060:Minimally Invasive Surgical Procedures / Q000379:methods; D016343:Monitoring, Intraoperative / Q000379:methods*; D010281:Parathyroid Hormone / Q000032:analysis*; D016105:Parathyroidectomy / Q000379:methods*; D011336:Probability; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D016896:Treatment Outcome
D010281:Parathyroid Hormone