We all go to doctors, and the first thing our communication begins with is laboratory research. And if for a specialist the data indicated on the results obtained are understandable, then an ordinary person is often confused even by a simple decoding of a blood test. HCT - this is how such a parameter as hematocrit is now denoted - is an important indicator of human he alth. Let's talk about it in more detail.
Hematocrit - what is it
Hematocrit is one of the conditional indicators of blood. It shows the percentage of the mass of erythrocytes to the total volume of biological fluid. The HCT indicator (blood test), the decoding of which can also be interpreted as the ratio of all blood cells to plasma, more often still determines the volume of red blood cells, because they make up 99% of the total number of blood cells.
The official name for this parameter is hematocrit, and inin common speech it is often called "thickness of blood." Hematocrit is a flask that is used to centrifuge biomaterial, but its name has taken root so well that it is very often used in official medicine.
How is hematocrit determined
As you know, blood consists of plasma (liquid part) and cells. Plasma is water in which proteins, enzymes, hormones, microelements are dissolved. The cells, represented by erythrocytes, leukocytes and platelets, have a different structure and perform dissimilar functions. When a blood test is deciphered, HCT is determined visually. For analysis, the selected venous or capillary blood is placed in a test tube and after adding an anticoagulant to it, it is centrifuged. At the same time, denser and heavier cells settle. The bottom layer is made up of erythrocytes, the middle layer is made up of leukocytes and platelets, and plasma remains on top. After that, the measurement takes place. So, for example, if the result indicates that 40% HCT (blood test), the decoding will mean that in a test tube with 100 μl of blood after it has been passed through a centrifuge, erythrocytes occupy 40 μl.
Today, there are two methods of how to determine the hematocrit. This is done using a centrifuge (in this case, the indicators will be indicated as a percentage) and using an automatic hematological analyzer. In the last study, the decoding of the complete blood count HCT will be determined as the ratio of liters to liters (l / l). It will look likeas follows:
- in the study on a centrifuge - 35%;
- when using a hematology analyzer - 0.35 l/l.
HCT (blood test), transcript. Norma
Hematocrit is not a constant indicator. It is often higher in men than in women. What are normal HCT values? A blood test (decoding) in children of the first year of life often shows significant differences from those in adults. As the patient grows older, this value gradually decreases. Pregnancy also affects this indicator. With its normal course, the hematocrit slightly decreases.
The following HCT values (blood test, transcript) are considered normal:
- norm in children of the first week of life - 42-66%, from 6 months to 2 years - 33-39%, from 2 to 6 years - 35-45%, from 6 to 15 years - 36-49%;
- girls from 15 to 18 years old can have a hematocrit of 36 to 46%, and boys - 37-49%;
- in women, hematocrit is normal from 33 to 47%;
- for men - 39-51%.
As you can see, the indicators have a fairly wide spread. In addition, considering the results, it is necessary to take into account that external factors can also influence them. For example, taking certain drugs (interferon alpha, blood thinners) can significantly affect the result.
Why is analysis prescribed
When a blood test is deciphered, HCT is one of its mandatory indicators, so it is always evaluated. This indicator has diagnostic value in the following cases:
- to confirm the diagnosis of anemia;
- with polycythemia (a group of diseases characterized by an increase in the number of red blood cells);
- for polyglobulia (diseases associated with high levels of protein in the blood);
- for control in the treatment of anemia.
In addition, when a blood test is deciphered for seriously ill patients, HCT allows you to determine the presence of internal bleeding, the level of dehydration. It is also an important indicator for patients after a blood transfusion, as it helps to assess the effectiveness of the measures taken.
HCT (blood test), transcript. Reduced value
Most often, a decrease in hematocrit can be observed with hypoplastic anemia. In this disease, the level of HCT can decrease to 15-25%. Symptomatically, this can be manifested by constant fatigue, headaches, dizziness, weakness. From the side of the cardiovascular system, tachycardia (increased heart rate), shortness of breath are observed. Externally, there is pallor of the skin, hair loss, brittle nails.
Another cause of low hematocrit can be overhydration. This pathology, characterized by an excess amount of water in the blood, can be the result of kidney failure, poisoning, viral or infectious diseases.
Hyperproteinemia (an increase in the amount of protein in the blood) can also be accompanied by a low hematocrit. Causeelevated blood proteins are pathologies of the liver (hepatitis, cirrhosis), malignant tumors, prolonged fevers, intoxication, chronic diseases of the heart and kidneys.
HCT during pregnancy
The decrease in hematocrit during pregnancy is physiological. However, the gynecologist leading the pregnancy is required to determine in a timely manner when low rates indicate the development of anemia. This is why blood tests are done regularly. HCT (norm) in women expecting a baby ranges from 31 to 35%. Its increase above 36% can signal dehydration, and indicators above 40% already indicate severe hypovolemia (decrease in circulating blood volume). The reason for this may be constant vomiting, swelling, excessive s alt intake.
A decrease in hematocrit in a pregnant woman below 30% can be a signal of increasing anemia, which means that the cells do not receive enough nutrients and oxygen. In addition, it leads to excessive stress on the heart, kidneys and other organs. Another reason for a decrease in hematocrit may be overhydration caused by the introduction of large volumes of intravenous infusions.
HCT increased
When the hematocrit is above 55%, we can talk about its increase. First of all, this means that there are too many cellular elements in the blood, that is, its viscosity increases. This threatens with increased thrombosis. Thrombosis can lead todevelopment of complications that can be fatal. The following conditions can cause an increased hematocrit:
- erythrocytosis, both primary (erythemia) and secondary, which can be caused by anoxia;
- pathology of the kidneys, which are accompanied by increased synthesis of erythropoietin;
- hydronephrosis or polycystic kidney disease;
- decrease in circulating blood volume (may result from burn disease, peritonitis, bleeding);
- dehydration.
What affects hematocrit
Despite all of the above, a moderate increase or decrease in hematocrit is not always a sign of the development of any pathology. Its increase may be associated with a slight dehydration of the body. Often this affects sedentary people who consume little fluid. Elevated hematocrit may result from excessive sweating, diarrhea, or vomiting.
High HCT can be observed in peoples living at high altitudes. The reason for this is constant hypoxia. Adapting to it, the body increases the number of red blood cells.
Hematocrit is elevated in athletes using anabolic steroids. If the blood test showed HCT above 50% (0.5), then the athlete is not allowed to compete as a doping user.
Smoking can also cause elevated hematocrit. This habit causes the body to be in a state of constant oxygen starvation, which stimulates the production of red blood cells. Howthe consequence is that the hematocrit increases, so even a he althy smoker will have a higher hematocrit than a non-smoker.
