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Lead screening — USMLE Step 3 MCQ

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HardPediatrics (well-child, chronic management)Lead screeningUSMLE Step 3

A 2-year-old who lives in a pre-1978 home has a screening finger-stick blood lead concentration of 22 micrograms/dL. He is asymptomatic, and the specimen was obtained after routine skin cleansing. What is the most appropriate next step?

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Correct answer: D — Obtain a confirmatory venous blood lead concentration within 2 weeks

The best answer is “Obtain a confirmatory venous blood lead concentration within 2 weeks”. Capillary samples can be contaminated and an elevated screening value must be confirmed venously. CDC recommends confirmation within 2 weeks for an initial concentration of 20–44 micrograms/dL. Chelation is not initiated solely from this capillary result, and lower concentrations still warrant exposure reduction and follow-up.

Reference: CDC: Recommended Actions Based on Blood Lead Level: https://www.cdc.gov/lead-prevention/hcp/clinical-guidance/index.html