{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,23]],"date-time":"2026-04-23T07:45:38Z","timestamp":1776930338282,"version":"3.51.2"},"reference-count":24,"publisher":"BMJ","issue":"11","content-domain":{"domain":["bmj.com"],"crossmark-restriction":true},"short-container-title":["BMJ Case Rep"],"accepted":{"date-parts":[[2020,10,12]]},"published-print":{"date-parts":[[2020,11]]},"abstract":"<jats:p>Serum intact parathyroid hormone (iPTH) levels are high or high normal in patients with parathyroid adenoma. Rarely these patients can have normal or low serum iPTH values. With sandwich immunometric assays, an exceptionally high serum iPTH level can lead to falsely low measurement due to the \u2018hook effect\u2019. Here, we describe the case of a 66-year-old female patient with PTH-independent hypercalcaemia which mimicked parathyroid adenoma. 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