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.

• All children: screen once at 9 to 12 months.
• If a child is on iron-fortified formula and otherwise low risk, you can consider screening at 15 to 18 months, which is often useful after the transition to cow's milk.

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.

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

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.
• 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: elemental iron 3 mg/kg/day, once daily or divided. The usual range is 3 to 6 mg/kg/day elemental iron. Start low for tolerance.
• Response goal: Hgb rises more than 1 g/dL in about 4 weeks.
• If it rises, continue iron for 1 to 2 months after the Hgb normalizes to replete stores.
• If it doesn't, 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: give elemental iron 3 mg/kg/day by mouth, once daily or divided.
Dispense: __ mL with an appropriate measuring device. Refills: __
Instructions: give with vitamin C-rich juice. 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.
• Give iron with vitamin C (fruit or juice) and keep milk and calcium away from the dose by 1 to 2 hours.
• 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]. 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.
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, counsel on administration (vitamin C, avoid milk around dose) and diet (iron-rich foods, limit milk under 16 to 24 oz/day).
Recheck Hgb in about 4 weeks, goal rise more than 1 g/dL. If improved, continue iron 1 to 2 months after normalization. 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 at 9 to 12 months, with repeat screening for high-risk kids.

Is ferritin worth adding?
Yes. It catches deficiency before anemia shows up. Just watch for inflammation, since ferritin rises with illness and can read falsely normal.

How fast should the Hgb rise?
About more than 1 g/dL in 4 weeks on adequate elemental iron. If it doesn't, recheck adherence, dosing, and absorption before broadening the workup.

Iron-deficiency anemia in kids is one of the most fixable problems you'll see, as long as you confirm it, dose by elemental iron, 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.

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 July 2026.