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The Leukemia/Bone Marrow Transplant Program of BC

Blood Cancer Basics
Hematology Basics

What Is Hematology?

Hematology refers to the study of the blood and blood-forming tissues. It has two major components:

  1. Benign or general hematology
  2. Malignant hematology described as cancers of the blood and blood-forming tissues.

Normal Blood Components

Whole blood consists of four components:

  1. Red Blood cells
  2. White Blood cells
  3. Platelets
  4. Plasma

Red Blood Cells

Red blood cells contain a protein called hemoglobin. Hemoglobin has the unique ability to pick up oxygen as they enter the small blood vessels of the lungs. Hemoglobins carry the oxygen to the various tissues of the body where the oxygen is released to generate energy for survival.

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White Blood Cells

The white blood cell component consists of a number of different cells:

  • The neutrophil (or poly) is the most common. The poly forms the key defence against bacterial infection in the human body. Other similar cells are the basophils and eosinophils. These cells are all called granulocytes because granules are present in them.
  • The lymphocyte is the second most common white cell, and consists of B-cells and T-cells. These are important in fighting bacterial and viral infections as well as in recognising undesirable (cancerous) cells and destroying these before they can multiply.

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Platelets are tiny blood components that are critical in providing the initial plug that stops a laceration (or cut) from bleeding. However, mature clot formation requires the interaction of a number of proteins called coagulation factors that are found in the plasma. While patients with a low platelet count or malfunctioning platelets (such as after taking aspirin) are prone to bleed, patients with normal platelet counts and normal platelet function may still bleed if they lack one or more coagulation factors, for instance Factor 8 deficiency (Hemophilia A).


Plasma is the fluid part of blood that remains after the cells are removed.  It is a straw-coloured liquid primarily composed of water and various proteins, including coagulation (clotting) factors as noted above, albumin and antibodies. If a patient is deficient in any of these plasma components, replacement transfusion with a specific plasma product may be necessary.

How Are Blood Cells Formed?

Red blood cells, white blood cells, and platelets all develop from a common mother cell in the bone marrow called a stem cell.

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