PTH and parathyroid gland carcinoma: Case series studying solitary parathyroid adenomas with asymptomatic disease derived mean preoperative PTH levels of 186 pg/mL [20] and 165 pg/mL [21], while research studying parathyroid carcinoma yielded higher PTH levels of 714 pg/mL [22] and 1220 pg/mL [23].