Modified quick parathyroid hormone test in surgery of primary hyperparathyroidism

Aim. The aim of the current study was the improvement of intraoperative quick parathyroid hormone (PTH) test, enabling to receive the results in a shorter period of time and to reduce the cost of the test, comparing with the existing methods. Methods. 404 consecutive patients with primary hyperparathyroidism (PHPT) were included in the study. All patients were subjected to selective parathyroidectomy – by traditional or videoassisted technique. We performed two parathyroid tests – traditional and modified – in each patient. Blood was taken a) before skin incision, b) before cutting the parathyroid adenoma vessels and c) in 10 minutes after cutting the parathyroid adenoma vessels. We used immunochemiluminescent analyzer DiaSorin Liaison. Modified test for parathyroid hormone differed in the duration of reagents incubation – two times shorter than in traditional method, resulting in immune reaction break before plateau occurrence. The statistical analysis of the results was performed using Microsoft Excel 2010. Results. With 50% cut-off level for PTH level fall (between the maximal level – before operation or before cutting parathyroid adenoma vessels – and the level in 10 minutes after cutting the adenoma vessels), the sensitivity, specificity, positive predictive value and negative predictive value for modified test reached 92.73%, 60.00%, 97.81% and 30.00%, accordingly, comparing with 95.84%, 55.00%, 97.62% and 40.74% for conventional method. Cut-off level change to 40% improved the results of modified test application, and increased its sensitivity and negative predictive value (97.14%; 50.00%; 97.40%; 47.62%). Conclusions. 2 times reduction of incubation time with cut-off level change to 40% allowed to cut the duration of intraoperative test for parathyroid hormone by half, and to improve diagnostic accuracy of the test, and at the same time to preserve low cost of the test.