Iron-Deficiency Anemia in Kids: When to Screen, How to Confirm, and What to Do

Iron-deficiency anemia is common in early childhood and usually silent. Universal screening catches kids before learning and behavior take a hit.

Universal vs selective screening

Universal screening is recommended, but the AAP's July 2026 clinical report changed when that screening happens: timing is now tied to how the infant is fed, not one flat age for everyone.

• Breastfed infants: screen at 9 to 12 months.
• Formula-fed infants on iron-fortified formula, otherwise low risk: screen at 15 to 18 months, closer to the transition to cow's milk, rather than the earlier 9-to-12-month window this post used to recommend for everyone.

High-risk groups, consider earlier or repeat screening:

• Excessive cow's-milk intake.
• Prematurity or low birth weight.
• Special health needs: chronic infection or inflammation, chronic GI dysfunction, restricted diets, and other dietary risk factors for iron-deficiency anemia.

Repeat screening when appropriate:

• 15 to 18 months for high-risk children.
• 15 to 18 months and again at 2 to 5 years for children with special health needs or ongoing dietary risks.

New: universal screening for menstruating adolescents

The AAP's 2026 report also adds a recommendation that wasn't in this post before: universal one-time screening for menstruating adolescents, at least 1 year after menarche and no later than age 14, regardless of other risk factors. This is in addition to the early-childhood screening above, not a replacement for it, and it's easy to miss if you're only thinking about anemia screening as a toddler issue.

Age-based anemia thresholds (Hgb, g/dL)

• 6 months to under 5 years: under 11.0
• 5 to under 12 years: under 11.5
• 12 to under 15 years: under 12.0

A flag on these numbers, for Allison specifically: the AAP's July 2026 report may revise some of these age-based hemoglobin cutoffs, but the full report is paywalled and I couldn't confirm the exact revised numbers against the primary source. The thresholds above are unchanged from what this post has used since 2025. Before publishing this as fully current, pull the full AAP report and check this table specifically, it's the one piece of this update I don't have primary-source confidence on.

How to screen and confirm

• CBC is preferred. If a CBC isn't available, Hgb alone is acceptable for screening.
• Add ferritin when you can. It detects iron deficiency before anemia develops. Current ferritin cutoffs for iron deficiency: 20 ng/mL or lower for children age 10 and under, 30 ng/mL or lower for children 11 and older and for menstruating adolescents.
• One catch: ferritin is an acute phase reactant. Consider checking CRP if the child is ill, so you don't get a false-normal ferritin.

If hemoglobin is low: next steps

1. Focused history and exam

• Diet: excess cow's milk, or prolonged exclusive breastfeeding without iron?
• Lead exposure, pica.
• GI symptoms or blood loss, chronic illness, family history of anemia or hemoglobinopathy.

2. Confirm

• Repeat the CBC to rule out a one-off or a lab error.
• If the picture is atypical for iron-deficiency anemia (no microcytosis, normal RDW), start a broader workup: iron studies, lead level, hemoglobin electrophoresis, and GI evaluation as indicated.

3. If it's typical for iron-deficiency anemia

Common pattern: child under 3 years, dietary risk, no evidence of lead toxicity, otherwise healthy.

• Start a trial of oral iron plus dietary counseling.
• Dose: the AAP's 2026 report moved away from the old 3-to-6-mg/kg/day weight-based range in favor of simpler fixed dosing: 3 mg/kg/day elemental iron for younger children, and a flat 65 mg/day elemental iron dose for adolescents rather than calculating by weight.
• Vitamin C co-administration to boost absorption is no longer considered necessary. It's still fine to suggest, it's just not a requirement for the regimen to work.
• Response goal is now stratified by severity rather than one flat number: for mild anemia, expect the Hgb to normalize by the 1-month recheck. For moderate to severe anemia, expect a rise of 2 g/dL or more by 1 month, with full normalization sometimes taking longer. Plan Hgb rechecks at both 1 month and 3 months rather than a single 4-week check.
• If it's responding as expected, continue iron for 1 to 2 months after the Hgb normalizes to replete stores.
• If it's not, reassess adherence, dosing, and absorption (milk timing), check for ongoing blood loss, then broaden the evaluation.

Example order (liquid)

Ferrous sulfate oral solution (220 mg/5 mL = 44 mg elemental iron/5 mL).
Dose: elemental iron 3 mg/kg/day by mouth, once daily or divided, for younger children. For adolescents, a flat 65 mg/day elemental iron dose is now the simpler default rather than calculating by weight.
Dispense: __ mL with an appropriate measuring device. Refills: __
Instructions: vitamin C-rich juice can help absorption but isn't required. Avoid giving with milk, calcium, or antacids.

One thing to watch: calculate the dose by elemental iron, not by total ferrous sulfate. 220 mg ferrous sulfate per 5 mL is about 44 mg elemental iron per 5 mL.

Parent counseling that actually helps

• Limit cow's milk to under 16 to 24 oz/day. Too much displaces iron-rich foods and reduces absorption.
• Vitamin C (fruit or juice) with the dose can help absorption, but it's not required anymore. Keep milk and calcium away from the dose by 1 to 2 hours either way.
• Expect dark stools and possible mild constipation. Use fiber, fluids, and prune or pear juice.
• Use a syringe for dosing, since it's more accurate than a kitchen spoon. Rinse or brush teeth after liquid iron to prevent staining.
• Keep iron out of reach. An overdose can be dangerous.

EMR SmartPhrase

IRON SCREENING / IDA PLAN
Universal screening performed at [age], per feeding type (breastfed: 9-12mo; formula-fed: 15-18mo) or as menstrual-adolescent screening. Result: Hgb __ g/dL (threshold for age: __ g/dL).
If low: repeat CBC ordered to confirm. Ferritin (plus or minus CRP) ordered to assess iron stores (threshold: ≤20 ng/mL if age ≤10, ≤30 ng/mL if age 11+ or menstruating).
Dietary risk factors reviewed: [excess cow's milk / prolonged BF without iron / restricted diet / etc.]. Lead risk assessed: [yes/no].
If consistent with IDA: start elemental iron 3 mg/kg/day (or a flat 65 mg/day for adolescents), counsel on administration (vitamin C optional, avoid milk around dose) and diet (iron-rich foods, limit milk under 16 to 24 oz/day).
Recheck Hgb at 1 month: goal is normalization for mild anemia, or a rise of 2 g/dL or more for moderate to severe anemia. Recheck again at 3 months. If response is inadequate, evaluate adherence, absorption, and blood loss, and broaden the workup.
Follow-up planned: [date].

Frequently asked questions

Universal or selective screening?
Universal, but the timing now depends on feeding type: 9 to 12 months for breastfed infants, 15 to 18 months for formula-fed infants on iron-fortified formula. High-risk kids still get earlier or repeat screening, and menstruating adolescents now get a universal one-time screen at least 1 year post-menarche, no later than age 14.

Is ferritin worth adding?
Yes. It catches deficiency before anemia shows up. Current cutoffs are 20 ng/mL or lower for age 10 and under, 30 ng/mL or lower for age 11 and up or menstruating. Just watch for inflammation, since ferritin rises with illness and can read falsely normal.

How fast should the Hgb rise?
It depends on how severe the anemia was at diagnosis. Mild anemia should normalize by the 1-month recheck. Moderate to severe anemia should rise at least 2 g/dL by 1 month, with full normalization sometimes taking longer. Recheck at both 1 and 3 months rather than relying on a single check.

Do I still need to give iron with vitamin C?
Not as a requirement. Current guidance no longer treats vitamin C co-administration as necessary for the regimen to work. It's still reasonable to suggest, especially if a parent asks, but don't hold up a plan or overcomplicate counseling over it.

What about a teenager who's menstruating but otherwise looks fine?
Screen anyway. The new universal recommendation applies at least 1 year after menarche and no later than age 14, regardless of diet, symptoms, or other risk factors.

Iron-deficiency anemia in kids is one of the most fixable problems you'll see, as long as you confirm it, dose correctly, and recheck on schedule. Because lead and iron deficiency travel together, it pairs naturally with lead screening in children. If you want the thresholds and the iron dose on one page in clinic, the Clinical Desk Reference ($37 quick-reference) keeps them close.

Source: AAP Clinical Report, "Prevention, Screening, Diagnosis, and Treatment of Iron Deficiency and Iron Deficiency Anemia in Infants, Children, and Adolescents," Pediatrics, July 2026. The age-based Hgb threshold table above has not been re-verified against this report, see the flag under that section.

Education only. Use clinical judgment and your local guidelines.

Written by Allison Sowders, MSN, APRN, FNP-BC, a practicing primary care nurse practitioner and founder of Nurse Practitioner Mentor. Reviewed September 2026.