Red blood cell count (RBC)
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Red blood cell count (RBC)Full blood count

Red blood cell count (RBC)

May 3, 2022

Red blood cell count (RBC)

What is a red blood cell count (RBC)?

Red blood cells are the most common type of cell found in the blood. And it’s not surprising. The oxygen they carry is essential for cell metabolism.

In their mature state, red blood cells are small (only 6 µm) and biconcave in shape. When they pass through small blood vessels, they transform into a bell-like shape so that they can squeeze through.

As red blood cells mature in your bone marrow, they get rid of their nuclei. This extrusion of nuclei by mature red blood cells happens right before they leave the bone marrow. It creates more space for haemoglobin.

A red blood cell count, also known as an erythrocyte count, calculates the number of red blood cells in your blood. It is typically measured as part of a complete blood count (CBC).

Why is this analysis important?

Neutrophils are differentiated from other cells under the microscope by their segmented nucleus and neutral pink stain (hence the name Neutrophil). They respond to inflammation and fight bacteria mainly by their swallowing function (a process called Phagocytosis).

They also release powerful chemicals that help with tissue healing after injury.

What are some of the causes of a high red blood cell count (RBC)?

A high red blood cell count is a condition called polycythemia vera. If you have this medical condition, it means that your bone marrow is producing too many red blood cells. This can result in thickening of the blood, slow flow of blood, and eventually blood clots.

Various medical conditions associated with generalized hypoxia or overproduction of red blood cells typically cause a high red blood cell count, including:

  • Dehydration – a decrease in the liquid part of the blood (plasma) leads to a higher concentration of red blood cells

  • Lung diseases – chronic obstructive pulmonary disease (COPD) results in poor gas exchange, and ultimately, generalized hypoxia

  • High altitude – as you go higher, the amount of available oxygen decreases

  • Heart diseases – in some cardiovascular diseases, the venous blood can mix with the arterial blood. This results in reduced delivery of oxygen to the tissues

  • Kidney diseases – sometimes, hypoxia can prevent the kidneys from working properly. When the kidneys have impaired perfusion, they can stimulate the production of EPO, and as a result, increase the production of red blood cells

  • Blood disorders – any blood disorders that increase the haemoglobin’s affinity for oxygen can decrease oxygen supply to the tissues

  • Carbon monoxide poisoning – carbon monoxide binds to haemoglobin. And haemoglobin binds strongly to oxygen, which reduces the availability of oxygen to your tissues

What are some of the causes of a low red blood cell count (RBC)?

A low red blood cell count can be a sign of many health problems, including:

  • Vitamin B-12 or folate (vitamin B-9) deficiency – deficiencies in either of these vitamins cause megaloblastic anaemia, a condition in which the bone marrow makes large, abnormal, immature red blood cells (megaloblasts). These abnormal red blood cells are too large to exit the bone marrow and supply tissues with oxygen

  • Stomach ulcers – the lining of the stomach can bleed if you have a stomach ulcer. The bleeding eventually causes anaemia

  • Bleeding – loss of blood decreases the number of red blood cells, resulting in anaemia

  • Lupus – patients with lupus may have dangerous decreases in the number of red and white blood cells

  • Hodgkin lymphoma – when lymphoma cells spread to the bone marrow, they can crowd out and inhibit the normal, healthy cells that make new red blood cells

  • Leukaemia – leukaemia cells can form in the bone marrow and crowd out healthy cells that make new red blood cells

  • Multiple myeloma – myeloma cells can interfere with the normal, healthy cells in the bone marrow that make new red blood cells. About 60%-70% of people with multiple myeloma have anaemia at the time of their diagnosis