Serum Hepcidin Immunoassay - Laboratory to Marketplace

Inclusion Criteria: * Age at least 11 years * Subjects must give informed assent/ consent prior to the blood draw. Subjects that are minors (\<18 years) must have a parent or guardian give informed consent and the subject must give assent to participate in the study. * Willing to comply with all oral iron supplementation and follow up visits if they move to the Observation of Treatment Phase. * Able to communicate in English. Exclusion Criteria: * Acute febrile illness (Temp ≥100.4°F (38°C), or acute otitis media, gastroenteritis, pharyngitis or other URI, within the previous one week. * History of known hemoglobinopathy (e.g., thalassemia trait or sickle cell) * Any parenteral iron received in the 30 days prior to enrollment. * Presently taking oral iron supplements (except for iron as part of multivitamin or oral contraceptive pill) or has taken it in the 30 days prior to enrollment. * An allergy or hypersensitivity to oral iron sulfate. * Has received a blood transfusion in the 90 days prior to enrollment. * Any investigational drug use in the 30 days prior to enrollment. * Any known malignancy. * Receiving dialysis. * Known to be pregnant or currently breast-feeding. * Any lab abnormality, medical condition, or psychiatric disorder 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 study requirements.