American Society of Hematology 2026 guidelines for diagnosis of iron deficiency

BACKGROUND: Iron deficiency is the most common micronutrient deficiency, and when untreated progresses to anemia. Existing guidance on the diagnostic criteria for iron deficiency is limited and not evidence based. OBJECTIVE: These evidence-based guidelines of the American Society of Hematology (ASH) are intended to support patients, clinicians, and other health care professionals in their decisions about the diagnosis of iron deficiency taking a global perspective in all settings. METHODS: ASH established a multi-disciplinary guideline panel that included one patient representative and was balanced to minimize potential bias from conflicts of interest. The University of Kansas Health System supported the guideline-development process, including performing systematic evidence reviews on the prevalence of iron deficiency across populations and studies to inform diagnostic thresholds up to July 2025. The panel prioritized clinical questions according to clinical impact and high-risk populations. The panel used the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach, including GRADE Evidence-to-Decision frameworks, to assess evidence and make recommendations, which were subsequently open for public comment. RESULTS: The panel agreed on 5 recommendations. CONCLUSIONS: Key recommendations of these guidelines include serum ferritin thresholds for specific populations with the goal to prioritize the diagnosis of iron deficiency, irrespective of the presence of anemia, remarks for considerations of other diagnostic thresholds, and guidance on the diagnosis of iron deficiency in persons with inflammation. Gaps in the literature and research priorities were also identified.