The lab on your report is still using the old number. Most clinical laboratories print a ferritin reference range with the lower end near 12 ng/mL for women (sometimes lower). A result of 14 or 18 comes back “within normal limits.” Under the new ASH guidelines published September 16 in Blood Advances, a ferritin of 14 in a menstruating adult is iron deficiency, not a borderline result, and not a case to revisit only if symptoms worsen.
The threshold moved because the evidence had been pointing here for years. Iron deficiency affects an estimated 10 million adults in the United States. ASH’s own analysis found labs were missing up to 70% of high-risk cases under the prior diagnostic approach. The new thresholds reflect decades of clinical research showing that symptoms — fatigue, hair loss, poor recovery, restless legs — appear at ferritin levels well above the old 12 ng/mL floor that labs were using to flag anything.
Four thresholds, not one. The new guidelines set different cutoffs depending on who is being tested. Adults and menstruating or pregnant individuals: 30 ng/mL or below. Adults with heavy menstrual bleeding or pregnant individuals with anemia: 50 ng/mL or below. Children aged 9 months to 4 years: 20 ng/mL or below. Adults with inflammation from cancer, IBD, or chronic infection face a different problem entirely, which the guideline addresses separately.
Inflammation hides it. Ferritin is an acute-phase reactant — the liver makes more of it during inflammation, even when iron stores are low. A person with active IBD or cancer and a ferritin of 60 ng/mL may have iron deficiency that looks normal on a standard printout, because the inflammation pushed the number up. The ASH guideline sets the threshold for this group at ferritin below 100 ng/mL, or transferrin saturation below 20%, whichever triggers first. Iron deficiency in inflammatory disease is one of the most commonly missed clinical scenarios, and this is the first major US guideline to name a specific threshold for it.
Your lab hasn’t caught up yet. Labs update reference ranges slowly, sometimes not at all without a regulatory push. “The recommended ferritin cutoff numbers are now higher across all populations,” ASH stated in its release. “Some people who were previously considered not to have iron deficiency based on their test results may actually have iron stores low enough to meet the criteria.” If your ferritin sits between 12 and 30, your report will still say normal. The clinical picture has changed.
What to do with this. Ask for ferritin specifically — a standard CBC does not include it and will not catch iron depletion before haemoglobin drops. If your result falls between 12 and 30, bring the ASH press release to your clinician as context. If you have an inflammatory condition and your ferritin reads between 30 and 100, ask about transferrin saturation. The test exists; the threshold guidance now exists.
Want to understand where your ferritin sits against the clinical evidence? See our low ferritin guide — it walks through what each range means for fatigue, hair loss, and recovery, based on NICE guidelines and the Verdon BMJ RCT.