The primary objective of this study is to evaluate the treatment response of Injectafer vs. oral iron to baseline hepcidin levels to determine if any of these select IBD or Gastric Bypass patients may demonstrate to be inappropriate for oral iron therapy.

The primary objective of this study is to evaluate the treatment response of Injectafer vs. oral iron in patients with varying hepcidin levels correlating the treatment response/hepcidin levels to more common laboratory parameters such as ferritin and CRP (C-Reactive Protein) levels and possibly determine if any of these select IBD or Gastric Bypass patients may demonstrate to be inappropriate for oral iron therapy.

Inclusion Criteria:

• Signed informed consent
• Male or female subjects ≥ 18 years of age with clinical diagnosis of IDA secondary to IBD or Gastric Bypass
• Screening Hemoglobin (Hb) ≤ 11g/dL
• Screening Ferritin ≤ 100 ng/mL
• Female subjects who are of childbearing age must have a negative pregnancy test at screening and be practicing an acceptable method of birth control during the study

Exclusion Criteria:

• Hypersensitivity reaction to any component of IV Injectafer or oral iron
• Requires dialysis for treatment of chronic kidney disease (CKD)
• During the 30 day period prior to screening has been treated with IV iron
• No evidence of iron deficiency
• During the 30 day period prior to screening has been treated with a 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
• Active malignancy within 5 years. Basal or squamous cell skin cancer is not exclusionary
• Alcohol or drug abuse within the past 6 months
• Hemochromatosis or other iron storage disorders
• Pregnant
• Any other laboratory abnormality, medical condition, or psychiatric disorders which in the opinion of the Investigator would put the subject's disease management at risk or may result in the subject being unable to comply with the study requirements

Sponsor reserves the right to publish the results collected from all sites. PI may publish results from a specific site if there is no multi-site publication within 12 months of the conclusion, abandonment or termination of the study. PI must provide sponsor with copy of draft publication at least 60 days before the scheduled submission to allow sponsor to protect confidential information. PI must withhold submission of publication for 90 days to allow sponsor to seek patent protection.