Complete Blood Count (CBC)

The complete blood count (CBC) is one of the most frequently ordered blood tests. To understand this test, it is important to know that blood consists of two major parts: plasma and cellular elements. The plasma is the part of the blood that is liquid which allows the blood to flow easily. The other part of the blood consists of blood cells.

The major cells in the blood are white blood cells (WBC), red blood cells (RBC), and platelets. Each of these types of cells carries out specific and important functions.

The complete blood count test measures the quantity of all the different types of cells in the blood. It also provides some valuable information on other parameters related to each type of blood cell.

Complete blood count (CBC). Blood is collected by inserting a needle into a vein and allowing the blood to flow into a tube. The blood sample is sent to the laboratory and the red blood cells, white blood cells, and platelets are counted. The CBC is used to test for, diagnose, and monitor many different conditions.

The test gets a lot of information from your blood sample:

  • The number and types of white blood cells (WBCs). Your body has five types of white blood cells. All play a role in fighting infections. High numbers of WBCs, or of a specific type of WBC, may mean you have an infection or inflammation somewhere in your body. Low numbers of WBCs may mean you are at risk for infections.

  • The number of red blood cells (RBCs). RBCs carry oxygen throughout the body and remove excess carbon dioxide. Too few RBCs may be a sign of anemia or other diseases. In rare cases, too many may cause problems with blood flow.

  • How the size of your red blood cells varies. This test is known as red cell distribution width (RDW). For instance, you may have greater differences in red blood cell size if you have anemia.

  • Hematocrit. This means the portion of red blood cells in a certain amount of whole blood. A low hematocrit may be a sign of too much bleeding. Or it might mean that you have iron deficiency or other disorders. A higher than normal hematocrit can be caused by dehydration or other disorders.

  • Hemoglobin. Hemoglobin is a protein in red blood cells. It carries oxygen from your lungs to the rest of the body. Abnormalities can be a sign of problems ranging from anemia to lung disease.

  • The average size of your red blood cells. This test is known as mean corpuscular volume (MCV). MCV goes up when your red blood cells are bigger than normal. This happens if you have anemia caused by low vitamin B12 or folate levels. If your red blood cells are smaller, this can mean other types of anemia, such as iron deficiency anemia.

  • A platelet count. Platelets are cell fragments that play a role in blood clotting. Too few platelets may mean you have a higher risk of bleeding. Too many may mean a number of possible conditions.

  • Mean corpuscular hemoglobin. This test measures how much hemoglobin your red blood cells have.

Haemoglobin (g/L)

Optimal range: 138 - 151 g/L

The hematocrit test is often used to check for anemia, usually along with a hemoglobin test or as part of a complete blood count (CBC). The test may be used to screen for, diagnose, or monitor a number of conditions and diseases that affect the proportion of the blood made up of red blood cells (RBCs).

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Hemoglobin

Optimal range: 12 - 15.5 g/dL

Hemoglobin (Hb) is the iron-containing oxygen transportation protein in red blood cells. It's rate of binding oxygen depends on the number oxygen molecules already bound. 

 

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Mean Cell Volume

Optimal range: 75 - 95 fL/red cell

Mean cell volume indicates the average volume of red blood cells in the body. It is often measured as a part of the red blood cell indices in a comprehensive blood count test. The results of the red blood cell indices will tell a healthcare professional whether or not anemia is present and, if so, what type it is.

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Mean Corpuscular Haemoglobin (MCH)

Optimal range: 26.6 - 33 pg

Mean corpuscular (or cell) hemoglobin (abbreviated as MCH) is an estimate of the amount of hemoglobin in an average red blood cell. Hemoglobin is a substance in the blood that carries oxygen to the cells in the body from the lungs.

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Although closely related, mean corpuscular hemoglobin concentration (MCHC) and mean corpuscular hemoglobin (MCH) are distinct measurements. While MCH represents the average amount of hemoglobin in a single red blood cell, MCHC reflects the hemoglobin concentration in a given unit of packed red blood cells. As with MCV and MCH, calculating the MCHC can help healthcare professionals better assess anemia and other blood disorders.

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Mean Corpuscular Volume (MCV)

Optimal range: 80 - 96 fl

Mean corpuscular volume indicates the average volume of red blood cells in the body. It is often measured as a part of the red blood cell indices in a comprehensive blood count test. The results of the red blood cell indices will tell a healthcare professional whether or not anemia is present and, if so, what type it is.

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Mean Platelet Volume (MPV)

Optimal range: 7.5 - 11.5 fl

Mean platelet volume (MPV) is a calculation that indicates the average size of platelets in the blood. This measurement is typically done during a comprehensive blood count. An abnormal MPV is not, in it of itself, an indication of disease or disorder. MPV scores are compared against other types of blood counts to give a healthcare professional more information about a potential medical issue.

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Platelet count / Platelets

Optimal range: 150 - 400 µl

Platelet count is a measure of how many platelets are present in the blood. Platelets are one of three types of blood cell, and their role is to aid in blood clotting. All three types of blood cell are assessed with a comprehensive blood count, which can be done as part of a general health check up or in response to specific symptoms.

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Red blood cell distribution width (RDW) is a measure of the average size of the red blood cells. RDW is assessed as a part of a comprehensive blood count, along with measures of white blood cells and platelets. An abnormal RDW score is not, in and of itself, cause for concern. A healthcare professional will need to compare an abnormal RDW score to other facets of the comprehensive blood count to identify a potential disorder.

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Red cell distribution width (abbreviated as RDW) is a measurement of the amount that red blood cells vary in size. Red blood cells help carry oxygen in the blood.

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Red Blood Cells (Erythrocytes / RBC)

Optimal range: 4.2 - 6.1 cells/mcL

Red blood cells (RBCs) are the most plentiful type of cell in the blood (~40% to 45% of the body's blood supply). They carry oxygen to the tissues and organs. They also bring back carbon dioxide back to the lungs so that it can be removed (exhaled) from the body. Red blood cells get their color from the protein hemoglobin. RBCs are constantly being replenished and they have a lifespan of around 120 days. 

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White blood cells (Leucocytes / WBC)

Optimal range: 4.5 - 10.8 x10E3/µL

White blood cells are the muscle of our body’s immune system. They serve to identify invasive microorganisms, isolate them, destroy them, and remember their weaknesses for later. There are five types of white blood cells, and they’re all measured with a blood differential test. Typically, this test is ordered when a complete blood count comes back as abnormal.

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