Evaluate the Utility of Serum Hepcidin Levels to Predict Response to Oral or IV Iron

Inclusion Criteria: * Male or female subjects ≥ 18 years of age and able to give informed consent. * Iron deficiency is the primary etiology of anemia. * If using erythropoiesis stimulating agent (ESA), the subject must be using a dose consistent with package insert that has been stable for at least 30 days. * Doses of potential myelosuppressive medications have been stable for at least 30 days. * Females at risk of pregnancy must agree to use an acceptable form of birth control and have a negative serum or urine pregnancy test on the first day of dosing. Exclusion Criteria: * Hypersensitivity reaction to any component of Injectafer. * Requires dialysis for treatment of chronic kidney disease (CKD). * No evidence of iron deficiency. * During the 10 day period prior to screening has been treated with intravenous iron. * During the 30 day period prior to screening has been treated with a red red blood cell transfusion. * Any non-viral infection. * Known positive hepatitis with evidence of active disease. * Received an investigational drug within 30 days of screening. * Alcohol or drug abuse within the past 6 months. * Hemochromatosis or other iron storage disorders. * Estimated life expectancy of less than 6 months, or for cancer patients, an Eastern Cooperative Oncology Group (ECOG) Performance Status greater than 1. * Pregnant or actively trying to become pregnant (a definitive negative result on a serum or urine pregnancy test performed on the first day of dosing will be …