New evidence-based guidelines from the American Society of Hematology (ASH) recommend higher serum ferritin thresholds for diagnosing iron deficiency, potentially identifying patients whose low iron stores may previously have gone unrecognized.
Published inBlood Advances, the guidelines address variation in testing practices and diagnostic thresholds across different patient populations. Iron deficiency is the most common micronutrient deficiency worldwide and can occur with or without anemia, making appropriate laboratory testing important for identifying patients before the condition progresses.
The guidelines focus on diagnosis regardless of whether anemia is present. The five recommendations focus largely on serum ferritin, a marker of the body's iron stores. ASH recommends a threshold of 20 ng/mL or lower for children aged 9 months to 4 years and 30 ng/mL or lower for adults, including menstruating and pregnant individuals.
Higher thresholds are recommended in selected groups at increased risk. A ferritin concentration of 50 ng/mL or lower can support diagnosis in people with heavy menstrual bleeding and pregnant individuals with anemia.
Interpreting ferritin becomes more complicated in patients with inflammation because ferritin can rise as part of the inflammatory response, potentially masking depleted iron stores. For adults with conditions associated with inflammation, including cancer, inflammatory bowel disease, and infectious disease, ASH recommends diagnosing iron deficiency when ferritin is below 100 ng/mL or transferring saturation is below 20 percent.
Jacquelyn Powers, Chair of the ASH Clinical Practice Diagnostic Guidelines, says, "The guideline panel reviewed data from across the world when considering the prevalence of iron deficiency, as well as literature on accuracy of diagnostic tests in different groups of patients. The new recommended serum ferritin thresholds for the diagnosis of iron deficiency are higher relative to existing guidance, so more individuals will be recognized as being iron-deficient."
ASH is encouraging laboratories to consider evidence-based clinical decision limits for ferritin rather than relying solely on reference intervals derived statistically from apparently healthy populations. The society argues that conventional reference ranges can fail to flag results associated with iron deficiency, particularly when the condition is common within the reference population.
"The new global diagnostic guidelines for iron deficiency will be highly impactful," says Powers. "My hope is that by better recognizing people with iron deficiency, iron treatment will be started much earlier, which will prevent progression to iron deficiency anemia, improve symptoms related to quality of life like fatigue, and positively impact other important health outcomes. These will most notably occur in young children and in individuals who menstruate and/or become pregnant."
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