Screening tests are crucial for several reasons: 1. Early Detection: They allow for the early identification of toxic substances, which can be critical for timely medical intervention. 2. Public Health: These tests help monitor and manage potential public health threats, such as exposure to environmental toxins or drug abuse. 3. Forensic Investigations: Screening tests are often used in forensic science to detect the presence of drugs or poisons in criminal investigations. 4. Occupational Safety: They can be used to ensure workplace safety by detecting exposure to hazardous substances among workers.