Iron Deficiency Anemia in Adults: From Diagnosis to Treatment - A Practical Clinical Review

Abstract

Iron deficiency anemia (IDA) is among the most frequently encountered hematological disorders in adult clinical practice. Despite its high prevalence and generally effective treatment, IDA should not be considered an isolated laboratory abnormality because it often reflects an underlying disorder requiring identification and management. Chronic gastrointestinal or gynecological blood loss, impaired gastrointestinal absorption, increased physiological requirements, and insufficient iron intake represent the principal mechanisms of iron deficiency. Diagnosis requires integration of hemoglobin concentration, red-cell indices, serum ferritin, transferrin saturation (TSAT), and the clinical context. Ferritin is the most useful marker of iron stores in uncomplicated patients but may be misleading in inflammation, chronic kidney disease (CKD), malignancy, infection, and liver disease. Oral iron remains appropriate first-line therapy for many stable adults, with once-daily administration preferred and alternate-day dosing useful in selected patients with intolerance. Intravenous iron is appropriate when oral therapy is ineffective, poorly tolerated, inadequately absorbed, or when rapid repletion is required. This narrative clinical review summarizes contemporary evidence regarding diagnosis, etiological evaluation, oral and intravenous treatment, monitoring, and treatment failure, with special attention to gastrointestinal investigation and CKD.