Blood test

A blood test is one of the most important research methods, as it allows the doctor to obtain the necessary information about possible diseases. If the doctor has reason to assume that you have too many or few red blood cells, he may order an analysis for HCT. So: a blood test, HCT transcript, normal and abnormalities.

HCT blood test: transcript, normal

HCT blood test: transcript, normal

Blood consists of water, plasma and cellular components. It is about these blood cells and will be discussed. There are three main groups of blood cells - the so-called shaped elements:

  • red blood cells - red blood cells that are responsible for the saturation of body tissues with oxygen and nutrients;
  • leukocytes providing protection against foreign cells and pathogens;
  • platelets responsible for blood clotting.

HCT in the blood analysis indicates the proportion of all cellular components in the blood volume and is called hematocrit. Since red blood cells predominate in the blood cells, which account for approximately 99% of all cells, the hematocrit value is largely determined by their concentration.

Our body relies on the correct proportion of red blood cells to stay healthy. Studying the hematocrit will help the doctor diagnose certain changes in the body or confirm the assumption of the disease, will provide information about the patient's water balance. Also, HCT analysis will help determine how well our body responds to certain treatments.

The analysis is done for various reasons, but most often it is used to check for the presence of such pathologies:

  • anemia;
  • leukemia;
  • dehydration;
  • dietary deficiencies.

The HCT index can be determined both as a result of the total and as a result of a complete blood count. A full analysis also examines the level of hemoglobin and reticulocytes, young red blood cells. The doctor will review the general results of the blood test to get an idea of ​​the concentration of red blood cells.

For a laboratory hematocrit test, a small amount of blood is needed. Blood sampling is done by puncturing a finger or using a syringe from a vein on the arm. If the hematocrit test is part of a complete test, blood from a vein will be used. In the laboratory, the biological material is placed in a centrifuge, where the tube rotates at high speed, due to which the blood is divided into three parts, such as:

  • plasma is the liquid component of blood;
  • red blood cells;
  • an anticoagulant that is added to prevent blood from clotting.

Red blood cells are concentrated in the lower part of the tube, they are compared with the reference value, as a result of which they determine the HCT index of blood. Normal hematocrit levels depend on the gender and age of the patient.

When deciphering the HCT blood test, the rate for women is in the range from 34.9 to 44.5%. For adult males, the following HCT ranges are generally accepted - from 38.8 to 50%. Children under the age of 15 have a separate set of ranges for decoding HCT. This is due to the fact that the hematocrit in a child changes rapidly with age.

A clinical laboratory that analyzes test results will determine the normal hematocrit range for a child of a certain age. The decoding of the HCT blood test and the norm in children are shown in the table.


1-3 days

1 week

2 weeks

1 month

2 months

3-6 months

Up to 2 years

3-6 years old

7-12 years old

13-15 years old























What are the deviations from the norm?

Normal red blood cell concentration

The normal red blood cell concentration is about 4-6 million cells per microliter of blood, with some variations for women and men. The reasons for the decrease or increase in hematocrit values ​​are practically the same factors as for erythrocytes.

The condition in which the red cell level is elevated is called erythrocytosis. It can occur as a normal reaction of the organism, located in the mountains at high altitude. Under such conditions, oxygen starvation of cells occurs and the body begins to produce more red blood cells in order to increase the oxygen supply to the tissues.

However, erythrocytosis can be caused by a blood disease, for example, true polycythemia, when spontaneous overproduction of red blood cells occurs. High hematocrit can also be caused by:

  • congenital heart disease;
  • dehydration, edema of the kidneys;
  • pneumonia;
  • tuberculosis.

On the contrary, reducing the concentration of red blood cells in the blood leads to a decrease in hemoglobin - the so-called anemia. This can be caused by different types of anemia:

  • Hemolytic anemia, when the destruction of red blood cells occurs due to various circumstances: from infections to autoimmune diseases.
  • Bleeding With significant blood loss, the concentration of red blood cells is reduced, as the body does not have time to restore their balance. In severe cases, donated blood may be required to restore hematocrit.
  • Sickle cell anemia. This is a hereditary disease associated with a violation of the hemoglobin protein.

In addition, a drop in the level of red blood cells in the blood can be triggered by chronic renal failure, when the adrenal glands in small quantities produce the hormone erythropoietin, which stimulates the synthesis of reticulocytes. In this case, hormone therapy is necessary.

The main causes of low hematocrit are also:

  • bone marrow diseases;
  • chronic inflammatory diseases, such as pancreatitis;
  • lack of nutrients and trace elements such as iron or vitamin B12;
  • internal hemorrhage;
  • leukemia;
  • lymphoma.

It is worth noting that before you take your HCT test, you must inform your doctor about recent blood transfusions or pregnancies. These factors can significantly distort the objective results of the analysis.

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