This module is intended to orientate new users and students to essentials in a pathology diagnostic lab. Components fundamental to conduct a diagnostic test are patient samples, laboratory equipment and the method or technique used. Three chapters in this module explain the need to care for machines, proper method for collection of patient samples and principles of test methods. Safety and health implemented from the individual to infrastructure, equipment and housekeeping are discussed. Diagnostic tests in the four disciplines are listed as well as their purpose and interpretation. Finally, the management of every aspect of the diagnostic lab under the quality management system and regulation by internal and external quality assurance programmes are introduced in separate chapters. Detailed standard procedures for diagnostic tests are not included.