Screening and treating adolescents with iron deficiency: a synthesis of emerging evidence

Iron deficiency is common during adolescence and frequently occurs without anemia, leaving many affected adolescents undiagnosed when evaluation relies on hemoglobin alone. Even in the absence of anemia, iron deficiency may be associated with fatigue, impaired concentration, sleep disturbance, reduced exercise tolerance, and other functional symptoms. Adolescence represents a period of increased vulnerability because rapid growth, increasing iron requirements, menstrual blood loss, changing dietary patterns, athletic activity, and chronic inflammatory conditions may contribute to depleted iron stores. Emerging evidence supports a shift toward earlier recognition of iron deficiency, including broader use of serum ferritin in screening and more nuanced interpretation of iron status. Recent guidance supports laboratory screening with a complete blood count and serum ferritin in postmenarchal adolescents, while emerging consensus and physiologic data favor higher ferritin thresholds in selected clinical settings. Treatment should address both iron repletion and the underlying cause of deficiency. Oral iron remains appropriate for initial therapy for most adolescents, although dosing, tolerability, and adherence are important considerations. Intravenous iron provides an effective alternative when rapid repletion is needed, absorption is impaired, ongoing losses exceed oral replacement, oral therapy is not feasible or tolerated, or response to an adequate oral regimen is insufficient. Heavy menstrual bleeding warrants particular attention because iron replacement and control of menstrual blood loss should occur in parallel. Despite these advances, important adolescent specific evidence gaps remain, including optimal ferritin thresholds across pubertal development, particularly in nonmenstruating adolescents, treatment targets for iron deficiency without anemia, and comparative outcomes of oral and intravenous iron. This review synthesizes emerging evidence to provide a practical framework for screening, recognizing, and treating iron deficiency in adolescents while highlighting priorities for future research.