This paper indicates the tests available for measurement of inorganic lead uptake by the body. The tests are listed and then considered individually. In the light of recent great interest in lead as a health hazard, the best methods for screening are considered: this includes biological and biochemical tests. It is emphasized that the U.K. favours blood lead estimation, the EEC countries other than Britain use blood lead but are considering more widespread use of delta-amino laevulinic acid dehydratase estimation in blood. Some authorities in the United States of America, on the other hand, favour a free erythrocyte protoporphyrin test. The advantages and disadvantages are brought out and some tests are mentioned only in order to exclude them as unsuitable. Suitability of tests for industrial checks and general screening of the population are differentiated. The conclusion is that blood lead still provides the best overall check of lead uptake.