What is a hemogram? How is the Complete Blood Count done?

A complete blood count (hemogram) is a blood test that gives an idea about the general health status and diseases if any. Some values ​​related to the cells and cells in the blood circulation are measured.

There are basically 3 main cell groups in the bloodstream. The cells responsible for the transport of oxygen and carbon dioxide are erythrocytes (red blood cells). The hemoglobin molecule in erythrocytes allows oxygen to be transported between the lungs and other tissues by binding. Those involved in the immune system are white blood cells divided into subgroups such as neutrophils, lymphocytes, monocytes, basophils, and eosinophils. Cells that form clots in order to prevent the blood from coming out of the vein by collecting in the damaged area in the problems that occur in the blood vessels are called thrombocytes (platelets).

What is a hemogram test (Complete Blood Count)?

Hemogram is a blood test to determine the number and proportions of cells in the blood. As the cells in the bloodstream are produced in the bone marrow, it provides an indirect evaluation of the bone marrow.

The hemogram test, which is used to evaluate the general health status, the effect of the treatment, or the disease process, also has a guiding effect in the diagnosis stage for many diseases:

  • Infection and inflammation
  • Leukemia and other cancers
  • Bone marrow diseases
  • Anemia
  • Autoimmune diseases caused by the attack of cells in body defense on organs and tissues
  • Thalassemias including Mediterranean anemia
What is a hemogram? How is the Complete Blood Count done?

How is the hemogram test (Complete Blood Count) done?

Blood must be taken from the person for the hemogram test to be performed. It is not necessary to take blood on an empty stomach. While the blood sample taken can remain in a suitable condition for analysis at room temperature for up to 10 hours, if the storage process is carried out in the refrigerator, this period is up to 18 hours. Thanks to the substance called EDTA in the tubes with purple caps, the blood is prevented from clotting in the tube.

By breaking down some of the blood taken, the hemoglobin molecule inside the red blood cells is allowed to leave the cell. In the other part of the blood, the cells are counted by applying only dilution. Counting and calculation processes are performed automatically in blood counters.

How is the hemogram test (Complete Blood Count) reported?

The number of cells and calculated rates in the hemogram test are expressed by some abbreviations:

• Red blood cell count (RBC)
• Hemoglobin (HGB)
• Hematocrit (HCT)
• Red blood cell indices (MCV, RDW, MCH, MCHC)
• Platelet count (PLT)
• White blood cell count (WBC)

These parameters are reported according to whether they are lower or higher than the limit values ​​when creating the complete blood count result document. The limit values ​​used in this reporting process are according to the adult age group. Limit values ​​in children vary according to age and gender.

• Red blood cell count (RBC): The main function of red blood cells (erythrocytes) in the body is to transport oxygen and carbon dioxide, which are respiratory gases. Erythrocytes maintain these functions for an average life span of about 120 days. In automatic blood counters, the normal value of RBC in adults is between 3.8 and 5.3 million / ml. The number exceeds this limit in diseases such as smoking, living at high altitudes, heavy exercise, and increased production of polycythemia vera. Reduced erythrocyte count can be found in blood loss, anemia, and pregnancy.

• Average erythrocyte volume (MCV): The volume of a normal red blood cell varies between 80-100 fl. By detecting the increase or decrease in the volume, the underlying anemia is classified. While the volume of erythrocytes was found to be reduced in iron deficiency anemia and thalassemia; In anemias due to folic acid or vitamin B12 deficiency, the erythrocyte volume is higher than the upper limit value.

• Hemoglobin (Hb) and Hematocrit (Hct): The hemoglobin molecule in the red blood cell is released as a result of the breakdown of erythrocytes in the blood taken. Hemoglobin is measured directly using photometric methods. The average hemoglobin concentration is 11.7-15.5 g / dL. According to the World Health Organization, a hemoglobin value below 13 g / dL in men and 12 g / dL in women is called anemia.

The hematocrit value is calculated by multiplying the mean erythrocyte volume (MCV) by the number of erythrocytes (RBC). The normal Hct value in adult individuals is between 35-45%.

• Average erythrocyte distribution width (RDW): It is a statistical value expressing the distribution width of red blood cells. While this value is increased in iron deficiency anemia, it is normally found in thalassemia carriers.

• Average erythrocyte hemoglobin (MCH): This shows the average amount of hemoglobin contained in red blood cells. Its normal value is between 30-34 picograms. It is found low in iron deficiency anemia and thalassemia.

• Average erythrocyte hemoglobin concentration (MCHC): It is the percentage expression of hemoglobin in red blood cells calculated by dividing hemoglobin (Hb) into hematocrit (Hct). Its normal value is between 30-36%. In a normal erythrocyte, regardless of its size, as long as its shape does not change, the amount of hemoglobin is constant between 30-36%. MCHC is higher than normal in Hereditary spherocytosis disease, where the red blood cells have a spherical shape with a pale disc-like structure.

• White blood cell count (WBC): The number of white blood cells (leukocytes) involved in body defense varies in conditions such as infection, inflammation, bone marrow diseases, and immune deficiency. The normal leukocyte count is between 4,400-11,000 / mm3. The number of white blood cells may increase after conditions such as leukemia, lymphoma, the course of infectious diseases, or a heart attack that results in tissue loss. A decrease in the number of leukocytes may occur after diseases such as AIDS, the use of certain drugs, autoimmune diseases, bone marrow suppressing treatments such as radiotherapy and chemotherapy.

There are five types of white blood cells in the bloodstream, mostly neutrophils, and a small amount called eosinophils, basophils, lymphocytes, and monocytes. An increase in the number of lymphocytes is observed in leukemia and chronic infectious diseases. If the microorganism causing the infection is a bacterium, the neutrophil count will rise. Connective tissue diseases cause an increase in the number of monocytes. While the basophil count increases in hypersensitivity reactions, the eosinophil count is found to be high in the case of an allergic or parasitic condition.

• Platelet count (PLT): The life span of thrombocytes, which are the smallest cells in the blood circulation, is approximately 9-12 days. Platelets ensure that when damage occurs in the vessel wall, that area is covered with a clot. Normal platelet count is between 150,000-400,000 / ml. In situations of physical stress, exercise, trauma, and infection, the platelet count may temporarily be between 450,000 and 600,000. Platelet count over 600,000 is observed in various conditions defined as myeloproliferative diseases in which stem cells are overproduced in the bone marrow.


What is the hemogram test for?
A hemogram also called a complete blood count or a complete hemogram test is a group of tests performed on a blood sample. The hemogram acts as a large screening panel that checks for any diseases and infections in the body.

Are CBC and Hemogram the same?
A complete hemogram includes a series of tests that include a complete blood count (CBC, also known as a complete blood cell count) along with the Erythrocyte sedimentation rate (ESR). CBC is a test that provides information about blood cells such as Red Blood Cells (RBC), White Blood Cells (WBC), and platelets.

What is a differential hemogram?
Hemogram and Differential – A complete blood count is used as a screening test for a variety of disease states, including anemia, leukemia, and inflammatory processes.

Is it necessary to fast for a hemogram?
If your blood sample is only being tested for a complete blood count, you can eat and drink normally before the test. If your blood sample will be used for additional tests, you may need to fast for a certain period of time before the test. Your doctor will give you specific instructions.

What diseases can be diagnosed with CBC?

These are some of the health problems that can be identified by a CBC:

  • anemia (low iron)
  • autoimmune disorders.
  • bone marrow problems.
  • cancer.
  • dehydration
  • heart disease.
  • infection.
  • inflammation.

What does a whole blood test show?
Complete blood count (FBC)

This is a test to check the types and numbers of cells in your blood, including red blood cells, white blood cells, and platelets. This can help give you an idea of ​​your overall health and provide important clues about specific health problems you may have.

The page content is for informational purposes only. Items containing information about therapeutic healthcare services are not included in the content of the page. Consult your physician for diagnosis and treatment.

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