About Hematocrit Test l How Is The Hematocrit Test Done?

Hematocrit is the volume of the presence of red blood cells in the blood and it is measured in percentage. The hematocrit (Hct) test evaluates the percentage of the red blood cells in the blood and the doctor can deduce the kind of disease or condition a person is suffering from the result of the test.

How is the Hematocrit Test Done


Blood is taken as sample from the person and is put in a test tube with is then attached to a device called centrifuge in the lab. The centrifuge spins the test tube at very high speed, which separates the blood into the plasma (fluid component), the red blood cells and other blood cells. From there the proportion of the red blood cell percentage is calculated.

When is Hematocrit Test Ordered

A physician generally orders Hematocrit Test to have the complete blood count (CBC) and often it is done at regular intervals to monitor as well as diagnose various conditions like anemia and polycythemia even recovery rate from dehydration. At times while treating a patient suffering from anemia or to check the severity of ongoing bleeding are asked to have the hematocrit test.                                                                                       In the case of rheumatoid arthritis patients, the hematocrit has a different percentage than that of normal as the ailment is an autoimmune disease, affecting the blood too.

Understanding the Hematocrit Test Result

Normal Hematocrit percentage differs according to the sex, males: 40.7% – 50.3%, and the female: 36.1% – 44.3%.

Low hematocrit – People who suffer from low hematocrit percentage are anemic in nature. There can be several reasons for anemia and it can range from nutrition deficiency (folate, vitamin B12, iron), internal bleeding due to some surgery, traumatic injury, bleeding colon cancer, bone marrow problems, kidney failure, result of suppression by chemotherapy and even sickle cell anemia or even overhydration.

High hematocrit – Normally a person living in high altitude will have high hematocrit percentage due to the less oxygen available at heights, even people suffering from dehydration will show high test result, but if the latter is given proper fluid hematocrit will come down to normal. Patients suffering from conditions or ailments like erthyrocytosis, congenial heart disease, rheumatoid arthritis, pulmonary fibrosis, cor pulmonale, polycythemia vera and hypoxia (low blood oxygen level) will show high percentage in hematocrit test.


Often during pregnancy there is a slight decrease in the hematocrit value because of the presence of extra fluid in the pregnant person’s blood.