Home Medication and medical testsVarious medical tests What is the hematocrit in a blood test

What is the hematocrit in a blood test

by Alivia Nyhan
Published: Last Updated on

Knowing the value of blood components becomes important to assess the state of health in general or to identify if there is any alteration in the body. For this reason, it is common that when you go for a consultation with the doctor or as a requirement to apply for a job, they request a complete blood test, which includes the red blood cell count and which is called hematocrit.

Blood is made up of erythrocytes or red blood cells, leukocytes or white blood cells, platelets, and blood plasma. The proportion of each of these can reflect certain conditions of the organism and frequently more reference is made towards the number of erythrocytes. But if you are interested in knowing what the hematocrit is in a blood test , in this FastlyHealarticle we want to inform you about it and other related points.

Hematocrit test: what does it mean and what is it for?

In a blood test, the hematocrit refers to the solid proportion of the unclotted blood sample, composed mostly of red blood cells or erythrocytes , thus making up a part of a complete blood count. To do this, a blood sample is taken and stored in a test tube, either obtained through a finger prick or through a needle in the arm vein. In addition, it is not necessary to be fasting before the blood draw and it can be done at any time of the day.

This red blood cell test is performed to determine the amount of these cells in the blood and provide information that the doctor uses to know the state of health, either to counteract with normal values ​​or the ratio compared to other blood cells.

The doctor may request a hematocrit test if there is a suspicion of suffering from a disease or disorder that is reflected in an alteration in the values ​​of erythrocytes in the blood . Likewise, it serves as a method to follow up on a pathology that has already been diagnosed or to confirm that the treatment given is working correctly and that the body reacts appropriately to it.

It is important to mention that the hematocrit in a blood test only gives an overview of the number of red blood cells, but is not used as a decisive diagnostic test, since through it it is not possible to indicate what is causing the alteration in the values if this exists and, for this, it is necessary to resort to other tests that include other parts of the body, according to the symptoms that are had.

Hematocrit values ​​in a blood test

Although there is an average normal value of hematocrit in a blood test, it can vary depending on the age and sex of the person and the technique used in the laboratory for the red blood cell count. The value in men tends to be higher than in women due to the higher oxygen requirement by the muscles. In general, normal red blood cell values ​​in a blood test range from:

  • Newborns: 47% – 68%
  • 1 month old babies: 31% – 49%
  • Babies between 1 to 3 months: 30% – 36%
  • Babies between 4 to 6 months: 28% – 42%
  • 1-year-olds: 29% – 41%
  • Children between 2 to 6 years: 34% – 40%
  • Children 6 to 12 years: 35% – 46%
  • Children between 11 and 12 years old: 37% – 46%
  • Adult male: 40% – 54%
  • Adult female: 36% – 46%

On the other hand, some circumstances could slightly alter the results and not necessarily be related to a pathology, for example, living at a high altitude, certain medications, constantly smoking, having had a recent blood transfusion , suffering from severe burns or being pregnant. the latter because it increases the proportion of blood plasma.

Causes of low hematocrit in a blood test

When there is an alteration in the results of the erythrocyte count in the blood, it may be a low value of these cells and this indicates that something is happening in the body, that is, it is a symptom that something is not working as expected. Thus, some of the possible causes of low erythrocytes or red blood cells are:

  • Anemia: it can be produced by various causes, the same ones that decrease the production or the life span of red blood cells. Possible causes of anemia include those of genetic origin, such as hemoglobinopathies or enzymatic alterations.
  • Bone marrow disorder: immature cells or hematopoietic stem cells are found in this marrow that give rise to blood cells, so an alteration in this structure results in a decrease in the production of erythrocytes. Some conditions involved are tuberculosis, different types of metastatic cancer, leukemia and lymphoma, among others.
  • Hemorrhages: large blood losses usually cause low hematocrit values, both in internal bleeding, for example from a gastric ulcer, and from deep skin lesions or strong trauma, even suffering from heavy menstruation.
  • Increased hemolysis: premature destruction of red blood cells increases, which leads to a decrease in the amount of these cells in the blood. This increase in hemolysis could be due to osmotic disorders, autoimmune diseases, or infections such as malaria.
  • Nutritional deficiencies: the lack of essential nutrients for the manufacture of red blood cells is another cause of having a low hematocyte value in a blood test. It is mostly related to a deficiency of vitamin B12 , iron or folic acid.
  • Kidney disease: the deficiency in the functions of the kidneys due to some condition or kidney failure, causes a lower production of erythropoietin, which is a protein responsible for stimulating the formation of red blood cells, so the amount of these cells also decrease.

Causes of high hematocrit in a blood test

The other possible alteration in the results of a blood test in which the erythrocytes are counted is that there is an elevated value of red blood cells in the blood. The possible causes of a high hematocrit in a blood test are the following:

  • Dehydration: This condition decreases the amount of plasma in the blood, causing the hematocrit ratio to be higher. It is one of the easiest conditions to solve, since it is normalized by ingesting the necessary fluids.
  • Polycythemia vera: it is a bone marrow disorder characterized by an excessive increase in the generation of blood cells, mainly erythrocytes. The cause is unknown, but it is thought to be related to a mutation in a gene involved in activating blood cell production.
  • Secondary erythrocytosis: this disorder is often related to polycythemia vera, but it can be an independent condition. It is the abnormal increase only in the number of red blood cells and can have various causes, generally due to increased secretion of erythropoietin, a protein that stimulates the formation of erythrocytes.
  • Chronic lung disease: the high hematocrit value in a blood test can also be the result of an increase in the production of red blood cells as a way to compensate for meeting the oxygen demand in the body. This can occur when the lungs are unable to inhale enough oxygen, for example suffering from pulmonary emphysema or pulmonary fibrosis.
  • Congenital heart disease: the abnormality in any of the heart structures prevents the proper functioning of said organ, affecting blood circulation and, in turn, insufficient oxygen transport. To counteract this deficiency, the kidneys produce more erythropoietin to increase red blood cells and satisfy oxygen transport.

This article is merely informative, at FastlyHeal .com we do not have the power to prescribe medical treatments or make any type of diagnosis. We invite you to see a doctor in the case of presenting any type of condition or discomfort.

If you want to read more articles similar to What is hematocrit in a blood test , we recommend that you enter our category of Medication and medical tests .

You may also like

Leave a Comment