If my child is exposed to lead based paint will a blood test give a definitive answer as to whether he or she was poisoned?

No. A venous blood test is accurate but it is important to understand that it is only a snapshot in time. It shows the concentration of blood at the time that the blood test is administered. Lead levels decrease as the lead leaves the bloodstream and deposits itself in the body organs of the child. The fact that your child has a particular lead level does not mean that he or she has not had higher blood lead levels at other times. It depends on the actual date of the ingestion of the lead dust or lead based paint.