What is Hematocrit (PCV)?

Hematocrit (HCT) is the calculated volume percentage of red blood cells (erythrocytes) in your blood. Hematocrit is also called packed cell volume (PCV) or erythrocyte volume fraction.

Human blood contains red blood cells, white blood cells, and platelets suspended in a liquid called plasma. The word hematocrit means to separate blood. In a hematocrit test, the red blood cells are separated from the rest of your blood cells and plasma.

Why is this analysis important?

Hematocrit is important because red blood cells are essential to your survival. They contain a vital protein component called hemoglobin that binds to oxygen, which fuels all the cells in your body.

When red blood cells pass through your lungs, they bind to and transport oxygen to various cells in your body. On their way back to your lungs, they carry carbon dioxide to be exhaled. Hematocrit is a significant measurement as it can identify whether you have sufficient red blood cells for oxygen transportation and delivery.

What are some of the causes of high levels of Hematocrit (PCV)?

If your hematocrit is high, it means that you have more red blood cells than is considered healthy. High hematocrit may be caused by:

• Heart disease

• Dehydration

• Scarring or thickening of the lungs

• Bone marrow disease

• Obstructive sleep apnea

• Smoking and chronic obstructive pulmonary disease (COPD)

• Carbon monoxide poisoning

• Testosterone use

What are some of the causes of low levels of Hematocrit (PCV)?

If your hematocrit is low, it means that you have fewer red blood cells than is considered healthy. Low hematocrit may be caused by:

• Blood loss

• Iron and vitamin deficiency, including folate, vitamin B12, and vitamin B6

• Too much water in the body

• Kidney disease

• Thyroid abnormality

• Immune destruction of red blood cells

• Leukemia or other bone marrow problems

Other considerations

In some cases, hematocrit is caused because of low iron levels.