Final answer:
A blood lead level test can be helpful in diagnosing lead poisoning in a child who is experiencing symptoms such as apathy, decreased appetite, irritability, dizziness, confusion, ataxia, and HA.
Step-by-step explanation:
Based on the symptoms described, the child may be experiencing symptoms of lead poisoning. Lead poisoning can occur when a child is exposed to lead, which can be found in older homes or areas with industrial pollution. To help diagnose lead poisoning, a useful lab test is a blood lead level test, which measures the amount of lead in the blood.