Haematocrit

Haematocrit (also known as Hct) is a blood test that measures the percentage of the volume of whole blood that is made up of red blood cells. This measurement depends on the number and size of red blood cells.

Overview[edit | edit source]

Haematocrit tests are often used to check for anemia, usually along with a haemoglobin concentration test or as part of a complete blood count (CBC). The test can help diagnose these conditions and monitor their progress. It can also be used to monitor hydration status because the test results can be affected by the amount of water in the body.

Procedure[edit | edit source]

The haematocrit test is performed by taking a blood sample from a vein in the arm using a small needle. The blood is collected in a tube and sent to a laboratory where it is placed in a machine that spins it at a high speed. This separates the blood into three layers: the bottom layer is the red blood cells, the middle layer is the white blood cells and platelets, and the top layer is the plasma (the liquid part of the blood).

Results[edit | edit source]

The haematocrit is the ratio of the volume of red cells to the volume of whole blood. This ratio is expressed as a percentage. For example, a haematocrit of 40 means that 40% of the volume of blood is composed of red cells.

Normal Values[edit | edit source]

Normal values for haematocrit can vary between laboratories, but in general, they are:

Men: 38.8–50.0%
Women: 34.9–44.5%
Children: 36.0–40.0%

Abnormal Results[edit | edit source]

Abnormal results can indicate various conditions, including:

Low haematocrit: Anemia, malnutrition, overhydration, leukemia, lymphoma
High haematocrit: Dehydration, polycythemia vera, lung diseases, heart disease

See Also[edit | edit source]

Haematocrit Resources
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