New Iron Deficiency Rules Raise the Bar for Diagnosis

Many people may not be getting enough iron. In fact, recent estimates suggest that as many as one in three Americans have iron deficiency or iron deficiency anemia, and many of them may not realize it.

American Society of Hematology President Robert S. Negrin, M.D., said in a recent statement that iron deficiency and iron deficiency anemia are “among the most common yet neglected medical conditions globally.” He added that patients can live for months or even years with symptoms such as fatigue, weakness, dizziness, or trouble concentrating before the problem is identified. Iron deficiency can also point to more serious underlying health issues.

To address that gap, the American Society of Hematology has issued updated guidelines for diagnosing iron deficiency, a condition that can progress to iron deficiency anemia if it is not treated. The key change is that the blood test used to identify the condition now has a much higher cutoff, which means some people once considered “normal” may now be classified as iron deficient.

“The new guidelines are so important because historically we have missed a lot of affected people, even those who were able to have iron-specific labs drawn,” says Angela Weyand, M.D., a member of the ASH panel that developed the guidance and a clinical professor of pediatric hematology-oncology at the University of Michigan Medical School.

Here’s a closer look at iron deficiency, iron deficiency anemia, and what the revised recommendations mean.

Meet the Experts: Kelsey Martin, M.D., hematologist at Yale Medicine and assistant professor of medicine at Yale School of Medicine; Jerry Spivak, M.D., hematologist and professor emeritus at Johns Hopkins University School of Medicine; Angela Weyand, M.D., American Society of Hematology media expert and panel member and clinical professor of pediatric hematology-oncology at the University of Michigan Medical School.

What are iron deficiency and iron deficiency anemia?

Iron deficiency and iron deficiency anemia are two points on the same spectrum: the body does not have enough iron stored to make hemoglobin, the protein in red blood cells that helps carry oxygen. This can happen if you do not get enough iron in your diet, do not absorb it well, lose it too quickly, or need more of it than usual.

When the shortage becomes severe, it can lead to anemia, or too few red blood cells. That matters because red blood cells are needed to move oxygen to the body’s organs and tissues.

But hemoglobin is only part of the story. “Iron is needed for far more than red blood cells, such as neurotransmitter synthesis and oxygen delivery through myoglobin,” says Kelsey Martin, M.D., hematologist at Yale Medicine and assistant professor of medicine at Yale School of Medicine. “This is key because many patients feel exhausted and tired all the time, report brain fog, and short[ness] of breath even before anemia appears.”

Typical signs of iron deficiency include fatigue and problems with thinking or concentration, though some people do not notice symptoms until iron deficiency anemia develops. According to the American Society of Hematology, symptoms can include:

• Fatigue
• Pale or yellow skin
• Shortness of breath
• Chest pain
• Weakness
• Rapid heartbeat
• Pounding or “whooshing” in the ears
• Headache
• Craving for ice or clay
• Sore or smooth tongue
• Brittle nails
• Hair loss
• Poor sleep
• Lightheadedness or dizziness
• Cold intolerance
• Restless legs syndrome

Treatment for iron deficiency and iron deficiency anemia usually involves replacing iron with oral or intravenous medication. If an underlying cause is found, such as celiac disease, treatment for that condition is typically part of the plan as well.

How did the diagnosis guidelines change?

Even as experts became more aware of how common iron deficiency is and how important early treatment can be, there still were no evidence-based guidelines for the general population, Dr. Weyand explains.

Diagnosis relies on blood tests that measure ferritin, a protein that reflects the body’s iron stores, says Jerry Spivak, M.D., hematologist and professor emeritus at Johns Hopkins University School of Medicine. One reason iron deficiency is often missed is that many standard screenings do not include ferritin. Instead, patients are often checked for hemoglobin alone, which does not provide the same full picture, says Dr. Martin.

In the past, ferritin results were compared with general-population lab ranges, and only the most extreme values were considered abnormal. But iron deficiency affects far more than the small fraction represented by those cutoffs. Different labs also used different reference ranges, which created inconsistency from one test site to another.

The updated ASH guidance sets clearer ferritin thresholds:

• Children 9 months to 4 years: 20 ng/mL
• Adults: 30 ng/mL
• High-risk groups (e.g., pregnant people with anemia, people with heavy menstrual bleeding): 50 ng/mL
• Adults with inflammation (e.g., those with cancer, inflammatory bowel disease, or infectious disease): 100 ng/mL or transferrin saturation under 20%

If ferritin is below the range for a person’s specific group, that person is considered iron deficient.

The higher cutoff for some groups reflects the fact that ferritin is an acute phase reactant. “Any significant stressor can cause elevation,” Dr. Weyand says. “So individuals with inflammation or infection will have artificially elevated ferritin levels and thus their cutoff is higher.”

Why do the new ferritin cutoffs matter?

“Symptoms of iron deficiency are real and show up before anemia develops,” Dr. Martin says. Earlier diagnosis can help people receive treatment sooner, before symptoms become more severe or complications develop.

That matters for more than comfort. Finding iron deficiency early can help restore iron stores faster and may also lead doctors to the underlying cause. Since iron deficiency can result from blood loss or poor absorption, it can signal conditions such as celiac disease or inflammatory bowel disease. It may also indicate heavy menstrual bleeding or bleeding in the gastrointestinal tract, both of which deserve medical evaluation.

In other words, ferritin levels can offer important clues about overall health. “Patients should advocate to have their ferritin checked,” Dr. Martin says.