CBC: know how to identify what may be altered

A complete blood count is a blood test that assesses the cells that make up the blood, such as leukocytes, known as white blood cells, red blood cells, also called red blood cells or erythrocytes, and platelets.

The part of the blood count that corresponds to the analysis of the red blood cells is called the erythrogram which, in addition to indicating the quantity of blood cells, informs about the quality of the red blood cells, indicating whether they are of the appropriate size or with recommended amounts of hemoglobin inside, the which helps to clarify causes of anemia, for example. This information is provided by hematimetric indices, which are HCM, VCM, CHCM and RDW.

Fasting is not necessary for its collection, however, it is recommended not to perform physical activity 24 hours before the exam and to stay 48 hours without drinking any type of alcoholic beverage, as they may alter the result.

What is it for

The blood count is used to assist diagnosis and monitor the evolution of diseases that cause changes in the blood, such as:

• Anemias; Bone marrow disorders; Bacterial, fungal or viral infections; Inflammation; Cancer, especially leukemias or lymphomas; Changes in platelets, such as their increase (thrombosis) or decrease (thrombocytopenia); Monitoring of situations that may compromise the functioning of the marrow bone, such as during chemotherapy, for example.

In addition, the CBC is useful to monitor chronic diseases that can lead to anemia, such as kidney failure, rheumatoid arthritis, heart failure or lung diseases, for example.

How is done

The test is performed in an automated way using flow cytometry equipment, which has the function of counting, evaluating and classifying blood cells according to several established criteria.

However, even with the result provided by the equipment, it is necessary that a microscopic analysis, called differential count in blood smear, be done by a professional qualified in Clinical Analysis. The differential count consists of the differentiation of leukocytes and visualization of structures present in red blood cells or leukocytes. In addition, counting using the microscope allows the identification of immature cells and, thus, can assist in the diagnosis of leukemia, for example.

How to interpret the blood count

To interpret the blood count, the doctor must observe its results and check whether the values ​​are normal, high or low, in addition to correlating them with possible symptoms presented by the person and the result of other tests that may have been requested.

If you have had a blood test recently and want to understand what the result might mean, enter your details here:

Some situations that can be seen in a blood count are:

1. Red blood cells, red blood cells or erythrocytes

The erythrogram is the part of the blood count in which the characteristics of red blood cells, the erythrocytes, also known as erythrocytes, are analyzed.

HT or HCT - Hematocrit	Represents the percentage of the volume occupied by the red blood cells in the total blood volume	High: Dehydration, polycythemia and shock; Low: Anemia, excessive blood loss, kidney disease, iron and protein deficiency and sepsis.
Hb - Hemoglobin	It is one of the components of red blood cells and is responsible for the transport of oxygen	Discharge: Polycythemia, heart failure, lung disease and at high altitudes; Low: Pregnancy, iron deficiency anemia, megaloblastic anemia, thalassemia, cancer, malnutrition, liver disease and lupus.

In addition to the amount of red blood cells, a blood count must also analyze their morphological characteristics, as they can also indicate diseases. This assessment is made using the following hematimetric indices:

• MCV or Average Corpuscular Volume: measures the size of red blood cells, which may be increased in some types of anemia, such as vitamin B12 or folic acid deficiency, alcoholism or bone marrow changes. If it is reduced, it may indicate anemia due to iron deficiency or genetic origin, such as Thalassemia, for example. Learn more about VCM; HCM or Average Corpuscular Hemoglobin: indicates the total hemoglobin concentration by analyzing the size and color of the red blood cell. See what high and low HCM means; CHCM (mean corpuscular hemoglobin concentration): demonstrates hemoglobin concentration per red cell, being normally reduced in anemia, this situation being called hypochromia; RDW (Range of distribution of red blood cells): it is an index that indicates the percentage of size variation between the red cells of a blood sample, therefore, if there are red cells of varying sizes in the sample, the test may be altered, which can be a clue to the onset of iron or vitamin deficiency anemias, for example, and their reference values ​​are between 10 to 15%. Learn more about RDW.

Find out more details about the blood count reference values.

2. White blood cells (leukocytes)

The leukogram is an important test to help verify the person's immunity and how the body can react to different situations, such as infections and inflammations, for example. When the leukocyte concentration is high, the situation is called leukocytosis, and the reverse, leukopenia. See how to understand the white blood cell result.

Neutrophils	High: Infections, inflammation, cancer, trauma, stress, diabetes or gout. Low: Lack of vitamin B12, sickle cell anemia, use of steroids, after surgery or thrombocytopenic purpura.
Eosinophils	High: Allergy, worms, pernicious anemia, ulcerative colitis or Hodgkin's disease. Low: Use of beta-blockers, corticosteroids, stress, bacterial or viral infection.
Basophils	High: After removal of the spleen, chronic myeloid leukemia, polycythemia, chicken pox or Hodgkin's disease. Low: Hyperthyroidism, acute infections, pregnancy or anaphylactic shock.
Lymphocytes	Alto: Infectious mononucleosis, mumps, measles and acute infections. Low: Infection or malnutrition.
Monocytes	High: Monocytic leukemia, lipid storage disease, infection by protozoa or chronic ulcerative colitis. Low: Aplastic anemia.

3. Platelets

Platelets are actually fragments of cells that are very important because they are responsible for starting the clotting process. The normal platelet value should be between 150, 000 to 450, 000 / mm³ of blood.

Elevated platelets are of concern because they can cause blood clots and thrombi, with a risk of thrombosis and pulmonary embolism, for example. When they are reduced, they can increase the risk of bleeding. Find out what are the causes and what to do in case of low platelets.