Haematology is a branch of medical science that studies the morphology of blood and blood-forming tissues. It covers the cellular composition of blood, blood cell formation, haemoglobin synthesis and all related disorders. Haematological parameters are widely used to support diagnoses and treatment monitoring.

Haematology studies red and white blood cells and platelets, their relative proportions, general cell health and the diseases caused by imbalances between them. Red blood cells have several important roles, but their most important function is to carry oxygen (O₂) and carbon dioxide (CO₂). White blood cells are an indispensable part of the body’s immune defence system, while platelets play an essential part in blood coagulation. All cells are necessary, but they must be maintained in the right proportions or systems will break down.

In this context, for instance, anaemia is the shortage of red blood cells, a condition caused by various factors. Leukaemia is a condition in which the bone marrow produces too many abnormal white blood cells so that they displace erythropoiesis and thrombopoiesis, and lead to dangerous symptoms. Thrombocytopenia is a serious acquired condition or symptom of an underlying disease.

Haematology recognises such imbalances. One of the most important laboratory tests – the complete or full blood count (CBC/FBC) – can help diagnose these conditions so that appropriate treatment can be prescribed.