The American Society of Hematology (ASH) has published its first guideline on diagnosing iron deficiency, setting higher serum ferritin thresholds across several patient populations, whether or not anemia is present. The panel included pediatric and adult hematologists, a neonatologist, a maternal-fetal medicine specialist, a pharmacist, and a patient representative. Its goal was for generalists and specialists alike to apply the same thresholds.

Jacquelyn M. Powers, MD, MS, guideline chair, section chief of hematology at Texas Children's Hospital, and associate professor of pediatrics at Baylor College of Medicine, explained the recommendations in an interview with HCPLive.

Frequently Asked Questions

What Ferritin Thresholds Do the New ASH Guidelines Recommend?

The panel issued 5 recommendations using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach, based on evidence through July 2025. Most are conditional recommendations based on low certainty evidence.¹ The guidelines suggest the following:

• Adults, including menstruating and pregnant individuals: serum ferritin ≤30 ng/mL
• Children aged 9 months to 4 years without known or suspected inflammation: serum ferritin ≤20 ng/mL
• Certain high risk patients: serum ferritin up to ≤50 ng/mL
• Adults with anemia of inflammation: test both serum ferritin and transferrin saturation (TSAT), with iron deficiency considered at ferritin <100 ng/mL or TSAT <20%¹,²

Why Did ASH Raise the Ferritin Thresholds?

Commonly used lab values and thresholds miss a large number of patients who are iron deficient and could benefit from treatment. The panel compared thresholds of 15, 30, and 50 ng/mL, where most evidence on diagnostic accuracy, treatment response, and symptoms is concentrated.

A threshold of 15 ng/mL is the World Health Organization (WHO) cutoff. Evidence suggests 30 ng/mL may be a more appropriate physiologic threshold. Some data suggest certain patients feel better at ≥50 ng/mL, and that iron absorption continues until ferritin reaches 50 ng/mL. The panel evaluated each threshold separately by population, because prevalence and patient needs differ.

What Symptoms Can Iron Deficiency Cause Without Anemia?

Symptoms can include fatigue, weakness, dizziness, shortness of breath, rapid heartbeat, headache, and difficulty concentrating.² They can be subtle and are often dismissed when a patient's blood count is normal. This is why the panel deliberately focused on iron deficiency rather than iron deficiency anemia, since early detection allows intervention before patients progress to anemia.

Does a Normal Ferritin Result Rule Out Iron Deficiency?

Not necessarily. Many lab reference ranges flag ferritin values in the single digits as normal.

"Many providers are very busy," Powers said. "They'll order a lab test. If it's not flagged, then they may say, 'Oh, everything's normal. I've ruled this out,' and now I'm going to put anything related to iron outside of my mind and look for something else."

Inflammation can also raise ferritin even when iron stores are low. For adults with anemia of inflammation, which can occur with cancer, inflammatory bowel disease, or infectious disease, the guidelines suggest testing both serum ferritin and TSAT rather than ferritin alone. The panel made no recommendation for children with inflammation because of insufficient evidence.¹,²

Why Do Young Children Have a Different Threshold?

Young children are in a period of rapid growth and use iron more actively than adults. Their threshold does not mean they need less iron.

The panel compared 12 ng/mL, the WHO cutoff, with 20 ng/mL. Some data suggest children continue to absorb iron until ferritin reaches about 20 ng/mL, after which absorption may plateau. The ≤20 ng/mL threshold applies to children without known or suspected inflammation.¹

When May a Ferritin Threshold of 50 ng/mL Be Appropriate?

A higher threshold may be appropriate for some high risk patients, including individuals with heavy menstrual bleeding and pregnant individuals with anemia.¹,² These patients can progress quickly from iron deficiency to iron deficiency anemia unless they maintain a higher ferritin.

"I want to make sure that providers consider those things when they're looking at the guidance and apply it individually to their patients, as it may be relevant for some patients, or a different threshold may be appropriate for others," Powers said.

Which Patients Are at Highest Risk for Iron Deficiency?

Higher risk populations include pregnant or menstruating individuals, children, and people with gastrointestinal conditions, dietary restrictions, blood loss, or chronic health conditions.²

Should Iron Deficiency Without Anemia Be Treated?

The guidelines address diagnosis only. The panel chose to start with diagnosis because accurate identification must come before treatment. The new thresholds are intended to identify more patients who may benefit from iron therapy. ASH expects to release treatment guidance in 2027.²

How Can Laboratories Help Implement the New Thresholds?

The panel is advocating for laboratories at institutions and national health organizations to adopt the thresholds as clinical decision limits within their reference ranges. Results below the threshold would then be flagged automatically, which makes it easier for clinicians to act on them.

Editor's Note: Powers reported no relevant disclosures.

References

1. 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

2. American Society of Hematology. ASH sets new standards for diagnosing iron deficiency. Medical Xpress. September 16, 2026. https://medicalxpress.com/news/2026-09-ash-standards-iron-deficiency.html