Higher ferritin cutoffs could uncover missed iron deficiency

Clinical takeaway: Consider iron deficiency at higher ferritin levels than many laboratories currently flag as abnormal. The new ASH guideline recommends higher diagnostic thresholds and additional use of transferrin saturation in patients with inflammation to improve detection of iron deficiency before anemia develops.

The American Society of Hematology (ASH) has published its first clinical practice guideline on the diagnosis of iron deficiency, addressing longstanding variability in testing practices and diagnostic thresholds. The recommendations, published in Blood Advances, aim to help clinicians identify iron deficiency earlier and more consistently across adults, children, pregnant individuals, and patients with inflammatory conditions.

Iron deficiency affects an estimated 10 million adults in the US and roughly 2 billion people worldwide, yet many cases remain undiagnosed. ASH notes that symptoms such as fatigue, weakness, dizziness, shortness of breath, and difficulty concentrating are often overlooked until iron deficiency progresses to iron-deficiency anemia.

A central recommendation is the adoption of higher ferritin thresholds for diagnosing iron deficiency than have traditionally been used. The guideline panel concluded that older cutoffs, while highly specific, may miss many patients with clinically meaningful iron deficiency.

“These updated ferritin thresholds provide clear guidance in an area where consensus has been lacking,” said guideline chair Jacquelyn M. Powers, MD, MS. “We hope these recommendations empower patients to better understand and ask for the testing they need and that health systems adopt these thresholds for diagnosis.”

The guideline also provides specific recommendations for patients with inflammatory conditions, such as cancer, inflammatory bowel disease, and infectious diseases, in whom ferritin levels may be elevated despite depleted iron stores. In these patients, ASH recommends incorporating transferrin saturation alongside ferritin testing to improve diagnostic accuracy.

Although the guideline focuses on diagnosis rather than treatment, earlier recognition of iron deficiency may help facilitate timely intervention and prevent progression to iron-deficiency anemia. ASH plans to release separate guidance on treatment in 2027.

Recommended diagnostic thresholds

• Children aged 9 months to 4 years: ferritin ≤20 ng/mL
• Adults: ferritin ≤30 ng/mL
• Menstruating individuals: ferritin ≤30 ng/mL
• Pregnant individuals: ferritin ≤30 ng/mL
• Higher-risk groups, including individuals with heavy menstrual bleeding and pregnant individuals with anemia: ferritin ≤50 ng/mL
• Adults with inflammation (eg, cancer, inflammatory bowel disease, or infectious disease): ferritin <100 ng/mL or transferrin saturation <20%
• Use ferritin-based clinical decision thresholds rather than relying solely on laboratory reference ranges

Source: Powers JM, et al. (2026 Aug 24). Blood Adv. American Society of Hematology 2026 guidelines for diagnosis of iron deficiency