General Practice 2022

Hematócrit (Hct): what é and why está high or low

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Hematócrit (Hct): what é and why está high or low
Hematócrit (Hct): what é and why está high or low

Hematocrit, also known as Ht or Hct, is a laboratory parameter that indicates the percentage of red cells, also known as red blood cells, erythrocytes or erythrocytes, in the total blood volume, being important to identify and diagnose some situations, such as anemia, for example.

The hematocrit value can also reflect the amount of hemoglobin present in the red blood cells: when the hematocrit is low, it is usually indicative of a situation in which there is a decrease in the amount of red blood cells or hemoglobin, such as anemia, due to example. When it's high, it can be indicative of low fluid in the blood, which could mean severe dehydration.

See also how to interpret hemoglobin values.

Hematocrit reference values

Hematocrit reference values ​​vary by laboratory, but generally the normal hematocrit value is:

  • Woman: between 35 and 45%. In the case of pregnant women, the reference value is normally between 34 and 47%;
  • Man: between 40 and 50%;
  • Children from 1 year: between 37 and 44%.

The hematocrit value may vary between laboratories and must be interpreted together with the other parameters of the blood count. Even when there is a small change in the hematocrit value, it does not necessarily mean a he alth problem and, therefore, the result must be interpreted by the doctor who requested the exam, in order to make the diagnosis based on the analysis of the result of all the exams requested. and symptoms described by the person, so that treatment can be started if necessary.Learn how to understand the blood count.

What can be low hematocrit

Low hematocrit may be indicative of:

  • Anemia;
  • Bleeding;
  • Malnutrition;
  • Lack or decrease in vitamin B12, folic acid or iron;
  • Leukemia;
  • Overhydration.

Already during pregnancy, low hematocrit is usually a sign of anemia, especially if the value of hemoglobin and ferritin are also low. Anemia in pregnancy is normal, however it can be dangerous for both mother and baby if not treated properly. Learn more about anemia in pregnancy.

What can be a high hematocrit

The increase in hematocrit can occur mainly due to the decrease in the amount of water in the blood, with an apparent increase in the amount of red blood cells and hemoglobin, which is a consequence of dehydration.In addition, hematocrit may be increased in lung diseases, congenital heart diseases, when there are low levels of oxygen in the blood or in cases of polycythemia, in which there is an increase in production and, consequently, an excess of circulating red blood cells.

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