What is a complete blood count for?

What is a complete blood count for?

I get asked a lot what is a complete blood count for? so I’m writing this post to explain in detail what a complete blood is, why it is done, why people get a CBC done, why it is done, why people get a CBC done and what the results could mean. A CBC is done to determine the general status of your health, the blood test is carried out by True Health Labs to screen for, diagnose or to monitor any number of disorders and conditions that may be affecting blood cells such as infection, anaemia, bleeding disorder, inflammation or cancer.

Why you get tested

The complete blood count is part of a routine medical examination, the test will be ordered if you are suffering from signs and symptoms that are associated with a condition that affects your blood cells, or it could be done at regular intervals to see how a treatment is progressing or to check the status of a disease or it could be done because you are getting treatment that affects blood cells.

Is a sample required?

Yes a non-fasting blood sample is required, if you order your complete blood count through True Health Labs the sample will be taken by a phlebotomist at a local location, the CBC test results are usually back to you by email within three days.

Do you need to prepare for the test?

No, all you have to do is order your complete blood count online, you will be given a prescription form to take to a convenient location near you to have your sample taken.

What is a complete blood count for

What is a CBC?

The CBC ( complete blood count) is a bunch of tests that to check out the cells circulating in your blood, the test includes red blood cells, white blood cells as well as platelets, the main answer to your question what is s complete blood test for is it evaluates your overall heath and detects a wide variety of diseases such as leukemia, and or infections, blood cells are produced mainly in bone marrow and normally are discharged in the bloodstream as required, there are three types of blood cells checked out by a CBC.

Red blood vessel (RBC)

Red blood cells (RBC) are also called erythrocytes, they develop in the bone marrow, when mature they are released into the bloodstream, they contain a protein called haemoglobin that carries oxygen to all parts of the body, the normal lifetime of a red blood cell is 120 days. To keep up to the demand for red blood cells the bone marrow must keep producing more ted blood cells, RBCs only last for four months, some get lost during bleeding so the process is always evolving.

Red blood cells are normally equal in shape and size their appearance can be changed for a number of reasons like an iron deficiency, vitamin b12, or folate deficiency, a common condition that affects Red blood cells is anaemia caused by a low white blood cell count and a low haemoglobin. Anaemia can cause a number if diseases, if its found during the complete blood count more tests may be needed to establish the cause.

White blood cells

White blood cells WBC or leukocytes are cells that are found in the blood, tissues and the lymphatic system, WBCs are an integral part of the bodies immune system by protecting against infection, playing a role during inflammation and allergic reactions. White blood cells are produced in five types, lymphocytes, monocytes, basophils, neutrophils and eosinophils, each WBC has a different function.

White blood cells are an important part of a complete blood count when they are found in somewhat steady numbers there are no issues, however the number of WBCs can change up or down depending on what is happening in the body. For example, should an infection occur it can push the marrow to make an increased number of neutrophils to counteract a bacterial infection, additionally certain diseases like leukemia, can make irregular white blood cells multiply rapidly.

Blood test lab


Platelets are also known as thrombocytes circulate in the blood, they are small cell particles involved in blood clotting, an example where this could happen is an injury occurs and bleeding starts, platelets rush to the affected site to stop the bleeding by sticking and bunching together forming a plug. Platelets can also let out a chemical signal that attracts and encourages more platelets that gradually form into a blood clot at the affected site and stays there until the injury has healed.

If you are wondering what is a complete blood count for getting a platelet count done as part of the test is a way to discover if you have a condition or disease that is causing a low platelet count or a dysfunction of platelets, its possible that you could be at an increased risk of bruising and bleeding, a high platelet count could cause substantial clotting.

What is being tested in a complete blood count?

Actually there are three types of complete blood counts that you can have done at True Health Labs, CBC with blood smear, CBC without differential or CBC with differential plus platelets, CBC with differential plus platelets is the most common test ordered, it measures’ various parameters that include cell counts and the physical appearance of the cells.

A complete blood test will look at the red blood cell count in total, it will measure haemoglobin levels or the oxygen carrying protein in your blood because in general this level details the number of RBCs in the body, the test measures’ hematocrit levels that is the total of blood volume consisting in red blood cells.

RDCs indices gives valuable insights into the physical characteristics of the red blood cells, mean corpuscular volume or MCV is taken to measure the average size of the RBC, mean corpuscular hemoglobin concentration or MCHC is a measurement taken from concentrated haemoglobin inside the red blood cells and averaged out.

RBC distribution width is the size and variation of the red blood cells, a complete blood count may also measure a reticulocyte count, a RC is a measurement of the total count of newly formed and release red blood cells.

The total of white blood cells in your sample will be counted, also WBC or white blood cell differential could be included, this part of the complete blood count is done to test if the WBC is up or down, the white blood count differential measures’ the number of the 5 white cell types that are present, the counting of each individual white cell (lymphocytes, monocytes, basophils, neutrophils and eosinophils) can be reported in absolute numbers and or as a percentage of the total.

Platelet testing is a vital part of a complete blood count for because it counts the number of platelets in the blood sample, platelet size, number and characteristics affect the amount of time it takes for your blood to clot.


I hope that by now you are more aware of what is a complete blood count for, the test is done to establish if the number of ŔBCs, WBCs and platelets are outside the reference numbers that indicates the presence of one or more conditions or diseases, your doctor will then make a decision on what other tests are needed to determine what is causing abnormal results.

True Health Labs have trained staff that can evaluate the features and physical appearance of each blood cell such as the size, colour, shape and check for any abnormalities that could be in your blood sample, the test result is emailed to you after three days, you don’t need to fast, to find out more on where you can have a complete blood count done go to the True Health Labs website here.