In children, a blood lead level greater than what value is associated with decreased intellectual performance and other adverse health events?

• A. More than 5 ug/dl
• B. Exactly 5 ug/dl
• C. Less than 5 ug/dl
• D. More than 20 ug/dl

Answer: (B)

Lead exposure can hinder a child’s brain development, and the risk increases as blood lead levels rise. Clinically, 5 micrograms per deciliter (μg/dL) is used as a reference point: when a child’s blood lead level exceeds 5 μg/dL, there is an observed association with decreased intellectual performance and other health effects. Importantly, there is no known safe level, but this 5 μg/dL threshold is the value often cited for detecting risk. So, the value to compare against for the statement about being greater than it is 5 μg/dL; any level above that threshold is linked to adverse outcomes.