Subject and method: 1154 children (from 3 - 14 years old) were taken blood to test blood lead levels by ICP-MS method and to evaluate the intellectual capacity (Raven test, LPS3), reaction time test (simple visual - motor reaction time, simple audio - motor reaction time), memory test (pictures, numbers, words), behaviour test (DBC-P, Vanderbilt), physical index (BMI, Pignet) (depending on age); calculate the sensitivity and specificity of these test.