The blood in the veins consists of all blood cells and the remaining plasma. The plasma portion also contains beneficial proteins and other minerals. The ratio of cells in the blood to the total blood volume is called the hematocrit (Hct). Hematocrit is not just the total percentage of red blood cells in the blood, but the ratio of all cells to unit blood volume.
With the hematocrit test, any disease risk or severity, if any, risk status in terms of anesthesia before surgical operations, determination of the viscosity of the blood, whether there is blood loss in the patient, and whether there is any benefit if the patient is receiving treatment, are evaluated.
Hematocrit levels are not evaluated alone. The patient’s blood pressure, sedimentation rate, erythrocyte and leukocyte counts, platelet counts and other accompanying symptoms are evaluated together.
In healthy individuals, hematocrit values are usually:
- 36 – 46% in women
- 42 – 52% in men
While hematocrit values can be obtained with automatic blood counting machines, it can also be done by centrifugation method. The ratio of hematocrit value to hemoglobin value in normal blood is usually 3 to 1. Results that deviate from this count in automatic count results can be considered suspicious.
Immediate evaluation and medical intervention is required, as an extremely low hematocrit level may indicate acute bleeding in the patient. If the hematocrit value is low in the blood count, but the cell numbers are sufficient, it is observed that the cells in the blood are normal in number but small in volume. This can usually be seen in cases of hemolytic anemia in which young erythrocytes, which we call reticulocyte, increase. In this case, the bilirubin level may also increase.
Peripheral smear examination may also be required for detailed diagnostic evaluation in low hematocrit. With the peripheral smear, the structures of the cells, especially the shapes of the erythrocytes, are examined. If low hematocrit values are accompanied by abnormalities in kidney functions such as high blood urea levels, it may be necessary to evaluate for kidney failure or other kidney diseases.
In some cases, a bone marrow biopsy may be required as a detailed examination. Because low hematocrit can be a symptom of all causes of anemia. Damage, suppression, infiltration or invasion in the bone marrow can suppress cell production from the bone marrow. This indirectly causes a decrease in the blood hematocrit level.
Low levels of iron, iron binding capacity and transferrin in the blood may indicate low hematocrit due to iron deficiency.
Causes that increase the need for oxygen in the blood may cause an increase in the number of erythrocytes, resulting in an increase in the total number of blood cells and an increase in hematocrit levels. For example, hematocrit levels increase in smokers or those who go to high altitudes.
The most common causes of hematocrit increase:
- An increase in each cell group that makes up the blood increases the hematocrit value.
- Leukemias
- High altitude
- Cigarette
- Excessive water loss
- Excessive alcohol intake
- Medicines
- Dogmatile
- Hydroxyurea
- Steroids
- Tranexamic acid
- Polyethylene glycol
The most common causes of hematocrit reduction:
- Blood losses
- Diseases in which blood production is impaired
- Malnutrition
- Poisonings
- lymphomas
- Tumors that disrupt the bone marrow
- Certain foods (milk, grapefruit, caffeine, and bran)
- Medicines
- Aspirin
- Desmopressin
- Finasteride
- Glycerol
- Iboprufen
- Metformin
- Misprostol
- Side effects of treatments
- Radiation therapy
- Resuscitation therapy after trauma
- Chemotherapy
- Immunoglobulin therapy
- Cardiopulmonary bypass treatment
- Phlebotomy treatment