Table 1. Current indications for surgery in asymptomatic hyperparathyroidism and comparison with previous ones.

Measurement	2002	2008	2013
Serum calcium (>upper limit of normal)	1.0 mg/dL (0.25 mmol/L)	1.0 mg/dL (0.25 mmol/L)	1.0 mg/dL (0.25 mmol/L)
Skeletal	BMD by DXA: T-score < −2.5 at any site	BMD by DXA: T-score < −2.5 at any site	A. BMD by DXA: T-score < −2.5 at lumbar spine, total hip, femoral neck, or distal 1/3 radius B. Vertebral fracture by X-ray, CT, magnetic resonance imaging, vertebral fracture assessment
Renal	A. eGFR reduced by >30% from expected B. 24-hour urine for calcium >400 mg/day (>10 mmol/day)	A. eGFR < 60 cc/minute B. 24-hour urine for calcium not recommended	A. Creatinine clearance < 60 cc/minute B. 24-hour urine for calcium >400 mg/day (>10 mmol/day) and increased stone risk by biochemical stone risk analysis C. Presence of nephrolithiasis or nephrocalcinosis by X-ray, ultrasound, or CT
Age, years	<50	<50	<50

BMD, bone mineral density; CT, computed tomography; DXA, dual-energy X-ray absorptiometry; eGFR, estimated glomerular filtration rate ⁴⁸.