PTH and vitamin D deficiency: Laboratory testing revealed classic biochemical findings of vitamin D deficiency, including 25-(OH)D3 < 5 ng/mL (reference range, 20-57 ng/mL), calcium 7.3 mg/dL (reference range 8.4-10.4 mg/dL), parathyroid hormone 1187 pg/mL (reference range, 10-65 pg/mL), 1,25-(OH)2D3 17 pg/mL (reference range 15-75 pg/mL), phosphorus 2.1 mg/dL (reference range 2.3-5.6 mg/dL), and magnesium 2.0 meq/L (reference range 1.4-2.6 meq/L).