This standard specifies the procedure to be followed and the equipment necessary for the determination of lead in blood by Atomic Absorption Spectrophotometry, in a concentration range of 5 to 100 pg of Pb/100 ml of blood (0.24 to 4. 82 prnol/liter) applicable to the monitoring of occupational populations potentially exposed to metallic lead and its ionic compounds. The spectral interference caused by non-specific absorption, which takes place at the working wavelength, makes it necessary to use a background absorption correction system.