Laboratory measurements pre-operative: 25(OH)D, PTH, CBC/Diff, glucose, calcium, albumin, total protein, sodium, potassium, CO2, BUN, creatinine, ALP, ALT, AST, bilirubin, lipid panel, ferritin, folate, iron, total iron binding capacity, hemoglobin A1c, insulin, vitamin B12, PT/PTT, TSH, HCG, C-reactive protein.