Full Blood Count (FBC)

A Full Blood Count (FBC) is one of the most common and informative blood tests available, giving a broad overview of your general health. It measures the three main types of cell in your blood, red cells, white cells, and platelets, providing valuable insight into a wide range of conditions, from anaemia and infection to problems with clotting.

White blood cells

White blood cells are central to your immune system and help fight infection. This test measures the total count and the different types:

• White blood cell count (WBC): the total number of white cells
• Neutrophils, lymphocytes, monocytes, eosinophils, and basophils: the five types of white cell, each reported as both a percentage and an absolute count. The balance between them can point to infection, inflammation, allergy, and other immune responses

Red blood cells

Red blood cells carry oxygen around the body. These markers assess their number, size, and oxygen-carrying capacity:

• Red blood cell count (RBC), haemoglobin (HGB), and haematocrit (HCT): measure the quantity of red cells and their oxygen-carrying protein
• MCV, MCH, MCHC, and RDW: describe the size, haemoglobin content, and variation of your red cells, which helps identify and classify different types of anaemia

Platelets

Platelets are the cells that help your blood to clot:

• Platelet count (PLT): the number of platelets
• MPV, PDW, P-LCR, and PCT: describe the size and characteristics of your platelets, giving further insight into clotting health

Why it matters

Because it checks so many aspects of your blood at once, a Full Blood Count is a valuable first step in assessing overall health. It can help detect anaemia, signs of infection or inflammation, and clotting problems, as well as establishing a healthy baseline and monitoring existing conditions over time.