A complete Blood Cell Count (CBC) is a laboratory test that is commonly ordered. When this test is ordered, hematocrit is also checked. Blood is made up of many different kinds of cells. Hematocrit is the percentage of the blood volume that is made up of red blood cells only. Factors that can affect hematocrit levels are size of the red blood cells and quantity of the red blood cells. There are many reasons that a doctor needs to know this information. For example, perhaps he or she is looking for signs of anemia, some kind of deficiency, or leukemia.
Normal results vary, but in general are as follows:
- Male: 40.7 - 50.3%
- Female: 36.1 - 44.3%
Normal value ranges vary slightly among different laboratories.
The hematocrit (Hct.) is a percentage of the blood volume that consists of erythrocytes (red blood cells), or the volume in cubic centimeters (cc's) of red blood cells that are packed in a blood sample after it is spun in a centrifuge. A centrifuge is a device that separates the constituent parts of whole blood.
Approximate normal levels are for adult men, 47% and adult females 42%. The normal values for children depend on the age of the child and can from 35% to 49%.
Hematocrit values are very significant because they give evidence of hemodilution or hemoconcentration. These factors are important in different disease states. Note that while valuable, the Hct. is almost never tested solely on it's own, but rather in addition to other hematology (serology) testing like Hemoglobin. The hematocrit and hemoglobin levels are found on a complete blood count (CBC) test.
Hematocrit Is the mass of red blood cells, in a given volume of blood. The procedure of checking the hematocrit consists in takin-off blood from a vein, which is then combined with an anti-coagulant substance and it is distributed in a very narrow glass tube, which is strong span in a centrifugal device.
Following this operation blood is separating in the upper layer (plasma) and the lower layer, composed of red blood cells, which represents the hematocrit.
Hematocrit is defined as the volume of the layer of red blood cells (in percents) from the total volume of blood from the glass tube.
Normal hematocrit values:
- Male = 40-48%
- Female = 36-42%
- Children 2-15 years = 36-39%.
Increased hematocrit is rare, when the body loses more water through sweating, fever, with vomiting (dehydration) and in disease that is characterized by an excessive growth of the number of red blood cells.
Decreased hematocrit is seen in anemia, loss of blood or when fluids are consumed before bleeding.
Hematocrit is helping to put a more precise diagnosis of anemia.