1. Carrying out of a test or tests, examination(s) or procedure(s) in order to expose undetected abnormalities, unrecognised (incipient) diseases, or defects: examples are mass X-rays and cervical smears.

2. Pharmacological or toxicological screening consists of a specified set of procedures to which a series of compounds is subjected to characterise pharmacological and toxicological properties and to establish dose-effect and dose-response relationships.