COMPLETE BLOOD COUNT

Why is this test done? A complete blood count can provide lots of information and as such is widely used to help diagnose or monitor several health problems, such as anemia, infections, etc. It is often part of a complete health check-up.
How to prepare:
  • Blood will be drawn to do this test.
  • There are no dietary restrictions prior to this test.
Target Values:
  • Total white blood count – adults: 4.4 – 11.3 x 109/L
  • Neutrophils: 1.8 – 7.0 x 109/L or 48 – 78%
  • Eosinophils: 0.02 à 0.5 x 109/L or 0 – 4%
  • Basophils: 0 – 0.15 x 109/L or 0 – 1%
  • Lymphocytes: 1.3 à 4.5 x 109/L or 20 – 40%
  • Monocytes: 0.10 à 0.75 x 109/L or 2 – 8%
  •  – adults: 4.1 – 5.9 x 1012/L
  • Reticulocytes – adults: 20 – 80 x 109/L ou 0.005 à 0.025
  • MCV: 80 – 96 fl/cell
  • MCHC: 334-355 g/L
  • MCH: 27.5 à 33.2 pg/cellule
  • Hematocrit – adults: 0.36 à 0.50
  • Hemoglobin – adults: 123 à 175 g/L
  • Platelets – adults: 150 – 450 x 109/L
  • Sedimentation rate: 1 – 20 mm/h
  • Blood smear: normal appearance

Note that reference ranges may vary between laboratories

 

General Information

The complete blood count provides information on various blood elements, such as red blood cells, white blood cells and platelets. The various tests measure several characteristics of these elements such as their size, their number, their form, their relative proportion, etc.

White blood cells are cells of the immune system found in blood and lymph . Their role is to defend the body. There are five white blood cell lines: the neutrophils, the eosinophils, the basophils, the lymphocytes and the monocytes.

Red blood cells are responsible for the transport of oxygen in the blood. The hematocrit is the volume occupied by red blood cells compared to that total blood volume (in percentage). Hemoglobin is a part of the red blood cells. Mean corpuscular volume, mean corpuscular hemoglobin and mean corpuscular hemoglobin concentration can be calculated from red blood cell count, hematocrit and hemoglobin level. These calculations provide information about red blood cell volume and hemoglobin content. Reticulocytes are immature red blood cells.

Platelets are cell fragments that travel in the blood and play an important role in coagulation. The sedimentation rate is the speed at which red blood cells from a blood sample reach the bottom of the test tube, in specific conditions. A blood smear is a visual test in which a drop of blood is examined under a microscope.

What does an abnormal test result mean?

Several diseases or health problems can influence the various parameters measured in a complete blood count. Because it provides information about several elements, the complete blood count can be used to diagnose more precisely certain disorders.

What you need to know before the test

Before going for blood tests, a procedure or other exam, it is best to always bring a list of all the drugs you take (prescription, OTC and natural health products). Unless told otherwise, you should take your medication as usual on the day of the test. When in doubt, ask your pharmacist for more information.