ASH Updates Iron Deficiency Diagnostic Thresholds

New clinical practice guidelines published in Blood Advances by the American Society of Hematology (ASH) recommend higher serum ferritin thresholds for diagnosing iron deficiency. The recommendations apply with or without anemia and seek to reduce diagnostic variation and missed cases while minimizing overdiagnosis.

ASH convened a multidisciplinary panel that included one patient representative. A University of Kansas Health System team conducted systematic evidence reviews through July 2025. Using the GRADE approach and Evidence-to-Decision frameworks, the panel issued five recommendations after public comment. Evidence certainty was low for the ferritin recommendations and very low for the inflammation recommendation.

For children aged 9 months to 4 years without suspected inflammation, the panel suggested a ferritin threshold of ≤20ng/mL rather than ≤12ng/mL. For adults excluding menstruating or pregnant individuals, it suggested ≤30ng/mL rather than ≤15ng/mL. The same ≤30ng/mL threshold was suggested for menstruating and pregnant individuals. A threshold of ≤50ng/mL may be appropriate in selected higher-risk circumstances, including adults with symptoms or ongoing risk factors, people with heavy menstrual bleeding, and pregnant individuals with anemia.

For adults with anemia of inflammation, the panel suggested measuring both serum ferritin and fasting transferrin saturation (TSAT) rather than ferritin alone. Iron deficiency may be considered when TSAT is <20% or ferritin is <100ng/mL, but the panel did not recommend specific thresholds because prospective evidence was limited. No recommendation was made for children with inflammation.

The authors identified low or very low certainty of evidence as the guideline’s principal limitation. Screening recommendations were outside its scope, and local adaptation may be necessary. ASH said it will monitor emerging evidence and revise the guidance as needed; separate guidance on iron deficiency treatment is anticipated in 2027.

Sources: Powers JM, Lim MY, Achebe MO, et al. American Society of Hematology 2026 guidelines for diagnosis of iron deficiency. Blood Adv. 2026. doi:10.1182/bloodadvances.2025015950

American Society of Hematology. ASH sets new standards for diagnosing iron deficiency. Press release. American Society of Hematology; September 16, 2026. Accessed September 17, 2026.