Full Blood Count Test

Full Blood Count Test

Full blood count test (FBC) is a test used to check the overall health of a person. An FBC is arguably one of the simplest but most revealing blood tests.

FBC test - £48.00 – Results are ready within 24 hours

The result of an FBC test can indicate a variety of health conditions like anaemia, bleeding/clotting disorder or infections. In a full blood count, the following parameters are looked at.

  • Haemoglobin
  • Haematocrit (HCT)
  • Red cell count
  • Mean corpuscular volume (MCV)
  • Mean corpuscular haemoglobin (MCH)
  • Mean corpuscular haemoglobin concentration (MCHC)
  • Red cell distribution width (RDW)
  • Platelet count
  • Mean platelet volume (MPV)
  • White cell count (neutrophils, lymphocytes, monocytes, eosinophils, and basophils)

Components of Blood

There are four components of the blood known as

  • Red blood cells
  • White blood cells
  • Platelets
  • Plasma

Each of these components has a standard level in the blood and measuring each of them, and their sub-groups is vital in diagnosing a wide range of diseases

Red Blood Cells

Anaemia is a common blood condition characterised by a reduced level of haemoglobin or red blood cells in the blood. The level of the RBCs is measured using two main parameters— haemoglobin and haematocrit levels. The size of the RBCs is measured using the mean corpuscular volume (MCV). MCV determines how healthy your red blood cells are. An increased MCV level means that your red blood cells are swollen due to excessive intake of alcohol.

The RBCs are responsible for carrying and storing oxygen in the blood. Low levels of RBCs mean that your essential tissues and organs may not receive enough oxygen, which is necessary for carrying out important chemical reactions capable of releasing energy.

There are different types of anaemia, but the most common is the iron-deficient anaemia which means that iron is lacking in the body due to either insufficient iron in the diet or the inability of the body to absorb the available iron leading to reduced red blood cells in the body.

Anaemia due to iron deficiency expresses the following symptoms

  • Paleness
  • Shortness of breath
  • Lack of energy
  • Heart palpitations

The size of the RBCs is also used as an indicator of iron deficiency anaemia.

If your FBC test result shows that you are anaemic, you will need to carry out a further test that measures your ferritin levels to confirm the diagnosis.

Other common causes of anaemia include deficiency in vitamin B12 and folate, so if you have anaemic-like symptoms, you’ll need to run a full blood count test alongside vitamin B12 and folate blood tests. These three blood tests are usually sufficient to reveal the cause of anaemia, butif none of them discovers the cause of the anaemia, you will have to perform a colonoscopy or endoscopy to eliminate internal bleeding due to stomach ulcer.


Measuring the level of blood platelets during a full blood count can help in the diagnosis of blood clotting or coagulation disorders. Blood clotting is a process that prevents excessive bleeding whenever blood vessels are injured. Several blood proteins, like fibrin, work together with the platelets to form a mesh-work around the injured blood vessel to prevent excess blood loss.

Clotting – hyper-coagulation

Blood clotting is an essential body process, but if the blood clots easily and does not dissolve properly as the blood is being transported around the body, it may limit or block blood flow.

When a blood-clot forms in the vein, it is known as thrombus or venous thromboembolism while blood-clots in other small blood vessels are called Embolism. These two conditions are dangerous and require immediate medical treatment.

There are two common blood clotting conditions

  • Deep vein thrombosis (DVT)- blood clotting in deep veins like the leg veins.
  • Pulmonary embolism – blood clotting in the pulmonary artery that transports blood from the heart to the lungs.

Pulmonary embolism usually results from a DVT travelling from the veins in the leg to the heart and lungs. About 10% of pulmonary embolism originates from a DVT.

Symptoms of DVT

  • Swelling in the lower leg/calf
  • An ache in the swollen area
  • Warm, red skin around the swollen area
  • Pain that worsens when flexing the ankle
  • Chest pain
  • Dizziness
  • Dry cough or coughing out blood
  • Shortness of breath

The following are high-risk factors for developing blood clots

  • Overweight or obesity
  • Immobilised legs (broken leg, paralysis, being bed-ridden)
  • Receiving hormone replacement therapy

If you think you have a blood clotting disorder, it's advisable to quickly get a full blood count done to check if your platelets are within the normal range.

At London GP clinic, we can also carry out Pre-travel DVT profile during your full blood count test to check if you are at risk of having blood clots, especially before a long-haul flight.

If you are experiencing the symptoms specific to DVT or PE, we recommend that you immediately go to a hospital for an ultrasound investigation or an anticoagulant treatment.


Platelets disorders such as malfunctioning or low-level platelets can cause bleeding or haemorrhaging diseases. In this condition, the platelets are unable to function properly, leading to the slow formation of clotting and excessive bleeding.

Bleeding-related symptoms include

  • Heavy menstrual bleeding
  • Bleeding into joints
  • Unexplained and easy bruising
  • Excessive bleeding from a small cut

Thrombocytopenia is the deficiency of blood platelets leading to the symptoms listed above. It can be caused by an autoimmune condition known as lupus (rheumatoid arthritis) or other unknown causes.

Other bleeding disorders include Von Willebrand disease and Haemophilia, which are both inherited from parents.

Generally, haemorrhaging is caused by factors such as

  • Deficiency in vitamin K
  • Reduced red blood cells
  • Side effect from some medications

White Blood Cells

Measuring the level of white blood cells during a full blood count can tell if there is any form of infection in the body. High levels of WBCs, also known as leucocytes, is an indication of an infection.

The various types of white blood cells are measured during a full blood count.

  • Neutrophils
    It is a phagocyte capable of ingesting bacteria. High level of neutrophil indicates a bacterial infection
  • Lymphocytes
    An abnormally high level of lymphocytes is a sign of either cancer of the lymphatic system (non-Hodgkins lymphoma) or Hodgkins.
  • Monocytes
    Monocytes engulf pathogens like bacteria
  • Eosinophils
    It is involved in allergic reactions targeting microorganism larger than bacteria
  • Basophils
    It releases histamine as an inflammatory response to antigens.

The information gotten from FBC can tell you a lot about your general health, but you will have to see our expert GP before the test.

You can visit our clinic at Suite 15, 117A Harley Street, London, W1G 6AT for your full blood count test or call 020 70434318to book an appointment. At London GP Clinic, we perform FBC at £48.00, and you should expect your result in 24 hours.

* A blood draw fee of £50 is payable for blood tests, urine tests and swabs carry no surcharge.