For a blood lead test, a small sample of blood is taken from a child, via a fingerstick or by drawing blood from a vein. The blood sample is then analyzed by special equipment that determines the amount of lead in the child's blood. Most health care providers still send the sample to a laboratory for analysis, so the results will not be available right away. Some health care providers now have access to a handheld analyzer that can be used in the clinic or provider's office and can give results in minutes.

The results of a blood lead test are expressed in micrograms (µg) of lead per deciliter (dl) of blood. The Centers for Disease Control and Prevention (CDC) calls 10 µg/dl the "level of concern" because scientists studying large populations have observed adverse health trends in groups of childen with blood lead elevations at this level. In fact, research makes clear that lead affects children's intelligence and learning at levels far below 10 µg/dl. For children with elevated blood lead levels, CDC recommends that health professionals inform and educate a child's family about finding and reducing exposure to lead. Other actions, such as medical treatment, are necessary for children with higher blood lead elevations. For more information on follow-up care, contact CDC (www.cdc.gov/nceh/lead/lead.htm).