Can screening tests accurately detect elevated blood lead levels?
Blood lead concentration is more sensitive and specific than free erythrocyte proptoporphyrin (EP) levels, but can be affected by environmental lead contamination and laboratory analytic variation. In one study of 47,230 suburban and rural children, 4.7% had an elevated EP level, while only 0.6% had elevated BLL. Capillary sampling has false-positive rates of 3-9%, and false-negative rates of 1-8%, compared with venous blood lead levels.
