Full Blood Count Explained

online nutrition coaching, free radicals, antioxidants

As a personal trainer in London, I recommend my clients to get a comprehensive blood test done once a year, including the full blood count. If you are part of a private health insurance scheme, you may get an annual health-check as part of the package.

The full blood count covers red blood cells, white blood cells, and platelets.

Red Blood Cells

These are what give our blood it’s red colour. Red blood cells carry oxygen around the body, to all the cells of your body. These are the three main tests for red blood cells:

Hb: This is the test for haemoglobin, the iron-containing protein in red blood cells which carry oxygen through the bloodstream. If the level is too low, you have anemia (which can be caused by a hereditary disease called thallasoemia), symptoms of which include low energy and shortness of breath. Too high, and you have polycythaemia, which can result in blood clots.

MCV: This stands for Mean Cell Volume, the average size of your red blood cells. If they’re too small, this is known as microcytic, which can be caused by iron deficiency in the diet, or thallasoemia. Other causes include vitamin B12 or folate (B9) deficiency, or chronic alcohol consumption.

Hct: This stands for haematocrit, the percentage of your blood composed of red blood cells. This is affected by the volume of plasma, the liquid component of your blood, which should be around 50% of blood volume.

White Blood Cells

The role of white blood cells is to fight disease. A high white blood cell count, known as leukocytosis, normally indicates that the body is fighting infection. A low count, known as leukopenia, can be caused by vitamin B12/folate/iron deficiency, or bone marrow failure. The 4 types of white blood cells are lymphocytes (which fight viral infections), neutrophils (which fight bacterial infection), basophils (which fight allergies), and eosinophils (which fight parasitic infections such as giardia).


Platelets are clotting-agents, which help cuts and wounds to clot, in order to avoid excessive blood-loss. Platelets are made in the bone marrow. If your platelet count is too high, you have thrombocytosis, which can lead to blood clots inside your blood vessels. Too low, and you have thrombocytopenia, which can be caused by bone marrow failure or when your immune system attacks your platelets (an auto immune response). In extreme cases, a platelet transfusion may be required.

The Effects of Alcohol Consumption on Your Blood

Alcohol is toxic to all the cells of your body, and your blood cells are no exception. Alcohol inhibits the manufacture of blood cells, as it attacks the bone marrow, where blood cells are made. White blood cells are damaged and destroyed by alcohol, particularly neutrophils, the bacteria-fighters. This is why alcoholics get so many bacterial infections. Alcohol consumption also inhibits the manufacture and function of red blood cells and platelets.

(Dominic Londesborough is a personal trainer in London and an online nutrition coach)

Leave a Reply

Your email address will not be published.