Conducting a general blood test at the first call of the patient to the doctor has long become the norm in diagnosing diseases. Often, HCT is also evaluated in a blood test in a child. The data obtained in this case are subject to a comprehensive assessment, where each individual indicator is not informative in itself.
The hematocrit indicator carries information only on the volume of red blood cells. The informative value of HCT in a blood test cannot be considered in isolation from other indicators. It should be supplemented with information on the amount, form and content of hemoglobin in red blood cells. The value of the hematocrit number is important for the diagnosis of various anemia.
What is the hematocrit index?
The hematocrit number, or hematocrit, is one of the indicators calculated by the analytical study of blood. Hematocrit is the ratio of red blood cells to the total blood volume in the body. Symbol on the HCT form in a blood test.
The short name “hematocrit” originates from the name of the analyzer flask for the study. Another name that is suitable for hematocrit will be “density”. In some sources, an indicator is defined as the ratio of cells to total blood volume.
Visually, this indicator can be determined by pouring a little blood into the tube. When it settles, you can see two layers - a dark layer of settled cells and a light layer of blood plasma. The percentage of layers will be a rough example of calculating the required number.
What does HCT mean in a blood test? This is a hematocrit indicator that determines the level of red blood cells in the total volume, where they are 99%.
Hematocrit calculation and recording
In laboratory conditions, the ratio in percent of red blood cells is calculated. Counting is done manually or in a laboratory automatic analyzer. In some laboratories working on a foreign sample, the HCT in a blood test is measured as a liter in a liter.
For example, the same analysis in different mappings:
- Accepted Entry: 35%;
- Western entry: 0.35 L / L.
What to do if HCT in a blood test is lowered? Deviations of the indicator from the norm show quantitative changes in the composition.
How to get tested for HCT?
In order for the analysis to show the correct hematocrit, the patient should adhere to certain rules:
- exclude alcohol a day before blood donation;
- Do not eat fatty, meat, fried foods for 24 hours;
- exclude smoking;
- on the day of analysis do not eat, water in small quantities is allowed;
- Do not be nervous and avoid physical exertion;
- if breakfast cannot be dispensed with (diseases, pregnancy), you can include unsweetened cereal on water or an apple, weak tea without sugar.
The doctor warns the patient about these rules 24 hours before the analysis.
When is a hematocrit test indicated?
Hematocrit values are important for:
- anemia - with a general decrease in hemoglobin level;
- polycythemia - an excess level of red blood cells, the disease is characteristic of the elderly, rarely in adults and children;
- polyglobulia - an excess of protein;
- a sharp loss of fluid in the body;
- various bleeding.
Determining the number of hematocrit will be necessary when monitoring the treatment of various blood diseases and the general condition of the patient during operations with transfusion or dialysis.
How is hematocrit tested?
There is a blood sampling from the patient’s finger, but it is possible to take an analysis from a vein. Blood is placed in a special flask-hematocrit, a reagent is added to it, which will not allow it to clot.
The hematocrit is installed in a laboratory centrifuge for separation - separation of the layers. Rapid rotation causes heavy red blood cells to settle down. The mass after processing is divided into three layers:
- The lower one consists of red blood cells.
- Medium - from white blood cells and platelets.
- Upper - contains plasma.
Hematocrit is defined as the percentage of layers. Now more and more widely, analyzer machines are used to carry out research in laboratories.
Decipher and analyze HCT in a blood test in relation to other indicators should be exclusively a doctor.
Hematocrit rates in children, men and women
Hematocrit fluctuation indicates the level of blood concentration (how diluted it is). The number of hematocrit has different meanings for men, women and children. So, what should be the value of HCT in a blood test? The norm in children of different ages is:
- 1-3 days - from 45 to 67%.
- 30 days - from 31 to 55%, regardless of gender.
- 180 days - from 32.5 to 41% regardless of gender.
- 24 months - from 32.5 to 41% for boys.
- 24 months - from 31.5 to 41% for girls.
- 6 years old - from 31 to 40.5% for boys.
- 6 years - from 27 to 40.5% for girls.
For men, HCT will differ in blood counts. The norm in men is:
- From 20 to 50 years old - from 38 to 49%.
- From 50 to 65 years old - from 37.5% to 49.5%.
Women are characterized by their HCT in the blood test. The norm for women is:
- From 20 to 50 years old - from 33 to 45%.
- From 50 to 65 years old - from 34 to 46%.
Causes of Hematocrit Increase
High hematocrit is observed in diseases and conditions of the body, the cause of which is a change in the quantity or quality of red blood cells:
- a sharp loss of fluid by the body - dehydration;
- primary erythremia;
- peritonitis;
- renal pathologies;
- respiratory diseases;
- bone marrow disease;
- various burns;
- heart defects and disorders in the cardiovascular system;
- intestinal obstruction;
- various blood diseases;
- diuretic abuse.
A high number of the indicator is observed with various kinds of hypoxia and is a protective reaction of the body - an increase in the number of red blood cells and an increase in hemoglobin ensures the normal supply of oxygen to all cells of the body.
Increased hematocrit indicates either a sharp outflow of fluid from the body, or a pathological increase in the number of red blood cells. If symptoms of kidney and blood disease are observed, elevated hematocrit may confirm leukemia or a neoplasm in the kidneys.
An increase in the number of red blood cells is possible with increased bone marrow function - such a disease is called erythremia. Symptoms of the disease are red skin and palms. The hematocrit must be considered in combination with other indicators characterizing red blood cells - ESR, a color indicator of blood.
It is detected in smokers, mountain residents, climbers, people suffering from lung diseases.
Hematocrit below normal
A low hematocrit is determined below 20%. Such a decrease indicates the presence of anemia and other pathologies in which the volume of fluid in the composition increases.
HCT blood counts are lowered in the following conditions:
- pregnancy - the total plasma volume increases while maintaining the mass of red blood cells;
- continuous blood donation;
- anemia - a decrease in the number of hematocrit is the main confirmation of the disease;
- various types of poisoning - pale grebe, salts of heavy metals;
- renal pathologies that increase the volume of water during intravenous influences in their treatment;
- various liver lesions that cause a pathological concentration of proteins in the body and retain moisture;
- bleeding of various nature - the blood volume in the body was replenished with plasma, red blood cells have not yet recovered;
- severe infections - typhoid, malaria.
Despite the specific secondary value of the hematocrit index, its sharp deviations from the norm will be a signal for a more thorough examination of the patient.