Basic investigations

The chapter aims to provide a brief but thorough reference for the commonest urine and blood tests that medical students will encounter on the wards and in clinic. The chapter focuses in detail on the wealth of information provided by a simple urine dip, including signs of infection, haematuria, pregnancy (or ectopic pregnancy), and metabolic disorders. The chapter discusses in detail how to read a full blood count which can give clues not only to infection but also to chronic infection, leukaemias, parasites, allergy, iron deficiency, and many other disease processes. The chapter also discusses the use of the reticulocyte count to help differentiate between haemolytic anaemias (raised) and bone marrow failure (decreased, e.g. from cancer). A guide to findings on blood films is also given. The clotting cascade and clotting parameters are summarized. The commonest tests in clinical chemistry, including blood glucose, renal and liver function, and bone profile are also discussed. A guide to blood gas analysis, with common examples, is also covered, along with a systematic approach to electrocardiogram interpretation.