This is a compendium of laboratory procedures used in diagnosis and treatment of a range of adult and paediatric conditions. It aims to answer questions of what tests to give and what to derive from the results. It covers testing for subspecialty areas, including: cardiology; pulmonary medicine; gastroenterology; neurology; orthopaedics, rheumatology; haematology; endocrinology; genetics; infectious diseases; and environmental medicine.