What is the clinical significance of PCV?

PCV
Also known as: Packed cell volume; haematocrit
Related tests: Full blood count

This test is used to evaluate:

• anaemia (decrease of red blood cells),
• polycythaemia (increase in red blood cells),
• dehydration,
• blood transfusion decision, and
• the effectiveness of those transfusions.

The PCV is normally requested as a part of the full blood count (FBC). It is also repeated at regular intervals for many conditions, including:

• the diagnosis of anaemia,
• the treatment of anaemia,
• recovery from dehydration, and
• monitoring of ongoing bleeding to check its severity.

A decreased PCV indicates anaemia, such as that caused by iron deficiency. Further testing may be necessary to determine the exact cause of the anaemia.

Other conditions that can result in a low PCV include vitamin or mineral deficiencies, recent bleeding, cirrhosis of the liver, and malignancies.

The most common cause of increased PCV is dehydration, and with adequate fluid intake, the PCV returns to normal. However, it may reflect a condition called polycythaemia vera-that is, when a person has more than the normal number of red blood cells due to a problem with the bone marrow . More commonly polycythaemia is a compensation for inadequate lung function (the bone marrow manufacturers more red blood cells in order to carry enough oxygen throughout your body).

Pregnancy usually causes a slightly decreased PCV due to extra fluid in the blood.

Living at high altitudes causes an increased PCV - this is your body's response to the decreased oxygen available at these heights.