New ASH Iron Deficiency Guidelines

Tired all the time. Winded on the stairs. A headache that shows up most afternoons. Plenty of people across th country live with these symptoms for months, sometimes years, before anyone checks their iron stores. On September 16, 2026, the American Society of Hematology (ASH) released new clinical guidelines for diagnosing iron deficiency, and they changed what counts as "low."

The change matters most for the people already at highest risk. Here is who those people are, which symptoms deserve attention, and what the new numbers mean if you were once told your iron was fine.

What iron deficiency is

Your body stores iron in a protein called ferritin. It draws on that store to make hemoglobin, the molecule in red blood cells that carries oxygen from your lungs to every tissue. Iron also supports your brain, immune system, muscles, skin, hair, and nails.

Iron deficiency means that the store has run low. Left untreated, it can progress to iron deficiency anemia, where hemoglobin drops and oxygen delivery suffers. ASH describes iron deficiency anemia as the most common blood condition in the world.

The scale is large. ASH estimates that iron deficiency affects roughly one in three people, including about 10 million adults in the United States and 2 billion people worldwide. Treatment options are widely available. Diagnosis is where people fall through the cracks.

Who is at higher risk for iron deficiency

Some groups lose iron faster, absorb less of it, or need more of it. ASH names these as higher-risk:

• People who menstruate, especially those with heavy periods. Monthly blood loss draws steadily on iron stores.
• Pregnant people. A growing baby and placenta raise iron needs sharply. We cover this in more depth in this resource
• Young children, particularly between 9 months and 4 years old, when growth is fast and diets are still narrow.
• People with gastrointestinal conditions that limit how much iron the gut absorbs, or that cause slow bleeding.
• People with dietary restrictions that cut out the richest iron sources.
• Anyone with ongoing blood loss, from any cause.
• People with chronic health conditions, including cancer, inflammatory bowel disease, and long-running infections.

Being in one of these groups does not mean you are iron deficient. It does mean a missed diagnosis is more likely. One analysis cited by ASH found that up to 70% of iron deficiency cases in high-risk groups go undiagnosed, largely because screening is limited and labs use different reference ranges.

Symptoms of iron deficiency to watch for

Iron deficiency rarely announces itself. The symptoms build slowly and look like ordinary life:

• Low energy or fatigue that sleep does not fix
• Weakness
• Dizziness
• Trouble concentrating
• Shortness of breath with normal activity
• A rapid or pounding heartbeat
• Frequent headaches
• Pale skin

Each of these has a dozen possible explanations, which is exactly why iron deficiency gets dismissed as stress, poor sleep, or a busy season. A blood test settles the question. If several of these sound familiar and you fall into a higher-risk group, ask for your ferritin to be checked.

The new ferritin cutoffs from ASH

Iron deficiency is diagnosed with a blood test that measures ferritin. A result at or below a set cutoff means your iron stores are too low. Until now there was no agreed standard, and many labs used thresholds as low as 12 to 15 ng/mL, in line with older World Health Organization figures.

ASH raised the cutoffs for every group:

• Children 9 months to 4 years: 20 ng/mL or lower
• Adults, including people who are menstruating or pregnant: 30 ng/mL or lower
• Higher-risk groups, including heavy menstrual bleeding and pregnancy with anemia: 50 ng/mL or lower
• Adults with inflammation, such as cancer, inflammatory bowel disease, or infection: ferritin under 100 ng/mL, or transferrin saturation under 20%

That last group needs explaining. Ferritin rises when the body is inflamed, so a person with a chronic illness can show a "normal" ferritin while their usable iron is low. Transferrin saturation measures how much of the body's iron-carrying protein is actually loaded with iron, which gives a second view that inflammation does not distort the same way.

The practical meaning, in ASH's own framing, is that some people who were told they did not have iron deficiency may in fact meet the new criteria. That is especially likely if their result sat close to the old cutoff.

What to do if you were told your iron was normal

1. Find your last ferritin result. Most patient portals keep past lab values.
2. Compare it to the new cutoff for your group. A ferritin of 25 ng/mL in a menstruating adult, for example, now meets the definition of iron deficiency.
3. Bring the number to your doctor. Ask whether a recheck makes sense under the new guidelines.
4. Hold off on self-treating. Iron supplements taken without testing can mask the cause of a deficiency or build up in people who do not need them.

ASH expects to publish separate guidance on treating iron deficiency in 2027. For now, the diagnosis guidelines give patients and clinicians a shared, clearer starting point. At Brodsky Hematology, iron deficiency is part of our core work in benign hematology care and services, alongside other non-cancerous blood conditions.

For referring clinicians: a quick summary

The guideline was published in ASH's peer-reviewed journal Blood Advances and developed by a multispecialty panel that included a patient with lived experience of iron deficiency.

Key points:

• Serum ferritin cutoffs are now 20 ng/mL (ages 9 months to 4 years), 30 ng/mL (adults, including menstruating and pregnant patients), and 50 ng/mL (heavy menstrual bleeding and pregnancy with anemia).
• In inflammatory states, iron deficiency is defined as ferritin under 100 ng/mL or transferrin saturation under 20%.
• Guideline chair Dr. Jacquelyn Powers noted that consensus in this area had been lacking, and ASH has encouraged health systems to adopt the new thresholds. Many lab reference ranges have not caught up yet, so flagged results may not reflect the new criteria.
• ASH treatment guidance is expected in 2027.

For patients who meet the new criteria, have not responded to oral iron, or have an unclear cause, you can send a referral through our hematology referral page.

See a hematologist at Brodsky Hematology

If your symptoms line up with this list, or your last ferritin result sits near the new cutoff, a focused hematology evaluation can give you a clear answer. Dr. Max Brodsky is board-certified in Internal Medicine by the American Board of Internal Medicine and is a fellowship-trained hematologist who focuses on benign blood disorders, including iron deficiency and iron deficiency anemia.

Call our White Marsh office at (410) 653.4002, or ask your doctor to send a referral through our patient referral page. Brodsky Hematology is located at 9920 Franklin Square Dr, Suite 220, White Marsh, MD 21236.