A 3-year-old boy is brought to the pediatric clinic for irritability, poor appetite, and developmental delay. His parents live in a house built in the 1940s and mention that they have been renovating the old walls, which are covered in peeling paint. The boy’s mother has noticed that he occasionally puts his hands and toys in his mouth. On physical examination, the child has pallor, abdominal tenderness, and a bluish discoloration along the gumline (Burton’s lines). Laboratory tests reveal microcytic, hypochromic anemia and basophilic stippling of red blood cells.What is the most appropriate test to confirm the diagnosis of lead poisoning in this child?
