Related Experiment Video
Updated: Mar 27, 2026
Procurement of Parathyroid Glands from Living Donor Pigs and Ex Vivo Identification
Published on: August 1, 2025
Intraoperative tissue aspirate testing: A single-center experience and evaluation of criteria for parathyroid tissue
Jillian Kodger1, Natalie Merchant2, Joe M El-Khoury1
1Department of Laboratory Medicine, Yale School of Medicine, New Haven, CT, United States.
Background:
Intraoperative measurement of parathyroid hormone (PTH) levels in aspirate washings from excised tissue (aIOPTH) is an adjunctive technique used to confirm removal of parathyroid tissue. However, published protocols for aIOPTH testing vary, particularly in defining threshold values for confirming parathyroid tissue. This study assesses the diagnostic performance of both absolute aIOPTH values and aspirate-to-serum PTH ratios (aIOPTH:sIOPTH) in identifying parathyroid tissue, and reports biochemical cure rates in patients undergoing aIOPTH-guided parathyroidectomy.
Methods:
We retrospectively analyzed aIOPTH testing in patients undergoing parathyroidectomy at a single tertiary-care center. Absolute aIOPTH concentrations and aIOPTH:sIOPTH ratios were compared to final histopathologic diagnoses to assess sensitivity and specificity. Biochemical cure was evaluated in patients with primary hyperparathyroidism based on total serum calcium and PTH measurements obtained six-months postoperatively.
Results:
A total of 209 specimens from 103 patients (93% with PHPT, 34% with multiglandular disease [MGD]) were evaluated. Of these, 87% were histologically confirmed as parathyroid tissue, with aIOPTH values ranging from 50 to 5000 pg/mL. Absolute aIOPTH thresholds demonstrated sensitivities between 0.90 and 1.00 and specificities ranging from 0.00 to 1.00. Ratio-based thresholds maintained a sensitivity of 0.99 but showed lower specificity (0.08-0.42). Biochemical cure was achieved in 96.9% of single adenoma cases and 93.3% of MGD cases.
Conclusion:
While aIOPTH:sIOPTH ratios have been reported to offer strong diagnostic performance, our findings indicate more variable specificity in clinical practice. In this cohort, we observed higher diagnostic accuracy with absolute aIOPTH values and propose aIOPTH >5000 pg/mL be considered confirmatory for parathyroid tissue, with values between 1000 and 5000 pg/mL regarded as indeterminate.
