Blood is made up of water which contains a collection of solutes and cells.
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| Complete Blood Count, CBC |
The cells in the blood are divided into three groups:
Red blood cells are responsible for transporting oxygen from the lungs to the various tissues of the body.
White blood cells, which are part of the immune system, fight germs that enter the body from outside.
Platelets play an important role in the blood clotting process.
CBC is a routine test that measures the quantity and characteristics of the three types of blood cells.
When is the examination performed?
Examination is carried out in the following cases:
To assess the possibility of anemia or an increase in the number of red blood cells, it must be noted here that we are not talking about a decrease or increase in the amount of blood itself, but rather the number of red blood cells and the additional essential element, which is hemoglobin.
When there is a suspicion of infection or inflammation, where an increase in the number of white blood cells occurs.
Accompanied by some other tests that measure the performance of the blood clotting system, and to check whether there is a decrease in the number of platelets or an increase in them.
To assess the possibility of immunodeficiencies, which may be caused by a low white blood cell count or a type.
To diagnose blood cancers such as leukemia or lymphoma.
As a routine examination before a surgical procedure.
The at-risk category
Patients who suffer from infectious diseases that are transmitted through the blood, such as hepatitis, AIDS, and others, must inform the medical staff of this before the examination.
It is true that infectious diseases do not prevent a blood test, but the presence of such diseases requires the medical staff to take more precautions and caution in order to prevent the transmission of infection.
Related diseases
Diseases related to a blood count test include:
Anemia.
Polycythemia.
High white blood cell count (leukocytosis).
Leukopenia.
Thrombocytopenia.
High amount of platelets (thrombocytosis).
How to perform the examination
There are no special preparations before the test. In general, a blood count test is performed on a sample of venous blood.
This is done by drawing blood from the arm of the examined person, which is stretched and placed upside down on a flat surface or table. The examiner tightens a rubber band around the upper arm, in order to temporarily block blood flow in the hand as much as possible, and to confine the blood to the area from which the sample is taken by injection.
after examination
The puncture area should be pressed for several minutes. Other than that there are no special recommendations.
Warnings
general
Hemolysis that may result from poor handling of a blood sample is defined as the release of hemoglobin and other components within cells as a result of the destruction of red blood cells (RBC). Specifically, hemolysis is present if the free hemoglobin is greater than 0.3 g/L.
The effect on the results of the blood count due to the inaccurate destruction of red blood cells leads to a decrease in the number of red blood cells and hematocrit, while the values of hemoglobin (Hgb) and mean corpuscular volume (MCV) remain the same. The platelet count may also be inaccurate due to erythrocyte fragments.
Analysis of the results
A complete blood count test includes several components:
Red blood cells (RBC, Erythrocytes)
The following is checked:
1. Hemoglobin
Hemoglobin is the most important component of red blood cells, which is the most important cellular component of blood. Here are the normal values:
Low levels indicate anemia, while high levels indicate increased red blood cells. There can be several causes for each of these two cases.
2. Hematocrit
Hematocrit or the volume fraction of red blood cells. This value is often proportional to hemoglobin levels, and it expresses the percentage of red blood cells in the total volume of blood. We list the normal levels of hematocrit in the following table:
3. Mean Corpuscular Volume (MCV - Mean Corpuscular Volume)
The normal level, the mean globular volume, ranges from 79 to 93 femtoliters.
When there is a decrease in hemoglobin levels, this value is an indicator of one of the causes of anemia. Low values may indicate iron deficiency. As for healthy values, it can indicate the presence of anemia that accompanies chronic diseases.
High values indicate a deficiency of vitamin B12 or folic acid.
4. Mean Corpuscular Hemoglobin (MCH - Mean Corpuscular Hemoglobin)
The normal level of mean corpuscular hemoglobin ranges from 26.7 to 31.9 pg per cell. It is less used than the MCV - Mean Corpuscular Volume.
5. Mean Corpuscular Hemoglobin Concentration
The normal level of mean corpuscular hemoglobin concentration ranges from 32 to 35.9 grams per 100 milliliters.
Less commonly used than mean corpuscular volume (MCV). It is only elevated with one disease, hereditary spherocytosis, and is normally elevated in newborns.
6. Red Cell Distribution Width (RDW)
The normal level for measuring the distribution of red blood cells is less than 14.5% and is elevated in several cases, including iron deficiency anemia.
7. Reticulocyte Count
Reticulocytes are young cells. When the number of reticulocytes is large, it indicates an increase in the production of red blood cells. This scale is used to assess the presence of anemia.
In order to determine whether the scale is normal or not, it is necessary to calculate the proportion of the number of reticulocytes to the level of hemoglobin, since the production of red cells increases naturally in anemia.
White blood cells (leukocytes, WBC)
These white blood cells are divided into two groups:
The first group
Since neutrophils and lymphocytes are the two basic types. The proportion between these two types varies according to the different types of infection.
the second group
Other types of white cells, which are less important, include the following:
Eosinophils, which are elevated in an allergy or parasitic infection.
for monocytes
Basophils.
The correct value of white blood cells is presented in the following table:
The percentages of healthy white blood cells and normal pronunciations are given in the following table:
Platelets (Platelets, thrombocytes, PLT)
Platelets contribute to the functioning of the blood clotting system, so that their proper number contributes to the prevention of bleeding. Their number increases in cases of inflammation and pressure, and sometimes without a known cause (Essential Thrombocytosis).
Their number decreases if they are destroyed by the immune system or due to increased consumption in the event of bleeding.
Normal platelet values range from 150,000 to 450,000 platelets per microliter.