Non-diabetic in-center HD patients on stable doses of paricalcitol over past three months with intact parathyroid hormone (iPTH) in the therapeutic range (150-300 pg/ml) will be identified from review of the dialysis program electronic medical records. Woman in the reproductive age group (ages 18-55), excluding those women who have undergone hysterectomy, oopherectomy will undergo a serum β-HCG levels during the selection process. If β-HCG levels are positive these patients will be excluded from the study.