Complete blood count – CBC Normal Values

August 9, 2021 Helal Medical

A complete blood count (CBC) is a blood test for to measure its constituents (elements that make it). It is used to evaluate your overall health and also to diagnose some disorders, such as anemias and leukemias. In this article we discuss the following points:

What is Complete Blood Count?
CBC Normal Value and Differential White Blood Cell
Can blood count be used to diagnose different health conditions?
What can CBC test detect?
Requirements to undergo for CBC Test?
Summary

What is complete blood count?

It is called complete picture because it measures all the major components of the blood, which are the blood cells and hemoglobin. But it does not measure the plasma components, such as minerals, hormones and other metabolites.

What does complete blood count measure?

A complete blood count test measures all the major elements and features of the blood, including:

Red blood cells, which are sacs full of hemoglobin that carry oxygen.
White blood cells, which compose the immune system fighting infection.
Platelets, which have a big role in preventing blood loss through blood clotting.
Hemoglobin, the protein that carries the oxygen in red blood cells.
Other criteria including Hematocrit, which is the proportion of red blood cells to the fluid component, or plasma, in your blood.
See the image below for the blood composition.

BLOOD after being centrifuged in a test tube, showing the main elements of blood: the plasma and the blood cells. First to the left; is the normal blood.

CBC for disease diagnosis and Normal values

CBC showing increase or decrease of blood elements may indicate presence of an underlying medical condition that require more investigations. So, your doctor may request additional test if values are higher or lower than normal ranges. What are the normal ranges? to know, continue reading.

Normal CBC values

Normal values of blood pictures depends on different factors. Men values are different than women’s. children blood values are different than adult’s values. these differences correlate with the physiological needs for blood elements , which depend on the age and sex.

Red blood cell count	Male: 4.35-5.65 million cells/uL Female: 3.92-5.13 million cells/uL
Hemoglobin — Hematocrit	Male: 13.5-16.5 grams/dL (%) Female: 11.5-15 grams/dL (%) —– Male: 38-48% Female: 35-45%
White blood cell count	3,500 to 10,000 cells/uL
Platelet count	Male: 150,000 to 450,000/uL

Differential White Blood Cell

Blood Cell Count		Normal Range Values
Neuts.% (Neutrophils)		40% to 60%
Lymphs% (Lymphocytes)		20% to 40%
Monos.% (Monocytes)		2% to 8%
Eos.%. ( Eosinophils )		1% to 4%
Baso.% (Basophils)		0.5% to 1%
Neuts.# (ANC- Absolute Count)		1.70-7.00 x 109/L
Lymphs# (ALC – Absolute Count )		1.00-4.80 x 10⁹/L
Monos# (Number of Monocytes)		0.30-0.90 x 109/L
Eos# ( Number of Eosinophils )		0.05-0.50 x 109/L
Baso# (Number of Basophils)		0.00-0.30 x 109/L

Sample of Normal Blood Test (CBC):

Can the test be used for disease diagnosis?

CBC , though very helpful, is not really a definitive diagnostic test, as we cannot reach final causes if an illness from the blood count only. CBC results outside the normal values may or may not require follow-up, that will depend on your health condition and symptoms. You may need to undergo other blood tests, to accurately diagnose reason of your illness.

To understand let’s consider Hemoglobin test as a example. When the blood hemoglobin is lower than normal, it indicates anemia. But what type of Anaemia? Also from the blood cunt results , we are able to know what type of Anaemia, whether it is microcytic, normocytic or macrocytic. Also we can know if it is hypochromic or normochromic. Furthermore, you may need to do additional blood tests to measure your blood iron levels , B12, and other blood criteria to find out the cause of anemia.

What can CBC test detect?

CBC , though is not a definitive diagnostic test, But it is very useful to detect a variety of diseases and health conditions, including:

Anaemia, where Red Blood Cells or Hemoglobin are less than normal.
Also, it can detect some vitamin and mineral deficiencies.
Disease of the Bone Marrow.
Disorders like Thalassemia and Sickle Cell anemia.
Infections where CBC will show changes in White Blood Cells count and differential. Both low and high may indicate the presence of infection.
Some cancers can be diagnosed by CBC, like Leukemia and Lymphoma.
Side effects of medications (like chemotherapy) can be detected by the test.

When do you need to undergo for Blood Count Test?

There many reasons why your doctor may request a CBC test, including the following:

You are ill and have fever suspecting any kind of infection.
Signs that you are losing weight without obvious reason.
Cancer-like signs, is also a reason to ask for CBC test. Some of these signs are general weakness, bruising, or bleeding.
Taking medication daily, may require testing the blood, on regular intervals to make sure the medicines will not affect your blood counts.
Finally, it can be preformed as part of routine check-up.

Does Complete Blood Count Test require fasting?

Not like many blood test that require fasting, this test does not need fasting. So you can eat and drink normally before the test. All parameters included in CBC test are not affected by food or drink. Other tests that require fasting include the following:

Renal function tests.
Lipid profile test, (Total cholesterol, Triglycerides and lipoproteins),
Blood test for Iron level.
Fasting Blood glucose.

Summary

Complete Blood Count , is also called Complete Blood Picture or CBC. CBC test can tell us about the elements composing our blood, whether normal or abnormal. It can help in the detection of a variety blood diseases and infections. Therefore, it is recommended to include CBC test in the evaluation of any illness and as a part of routine check-up. But, CBC alone is not a definitive final test to detect the cause of the illness, other tests and investigations maybe required to reach the final diagnosis.

References for more reading:
– https://www.mayoclinic.org/tests-procedures/CBC
– https://familydoctor.org/
– https://www.verywellhealth.com/
– https://my.clevelandclinic.org/health/diagnostics/