Cholesterol screening testing is indicated for all healthy children between the ages of 9 and 11 years old and again between the ages of 18 and 21 years old. More frequent screening is indicated in those children with a family history. Tuberculin skin testing is indicated only for children who have TB exposure or who have risk factors (recent immigrants, close contacts, etc.) Blood lead level testing should be performed between ages 9 months and 1 year in children with exposure risks. Hemoglobin and hematocrit are indicated in healthy infants 9 months to 1 year to check for iron deficiency.