Hematocrit Test
The hematocrit test, also known as a packed cell volume (PCV) or erythrocyte volume fraction (EVF), is a blood test that measures the proportion of red blood cells in the blood.
Purpose
The purpose of the hematocrit test is to:
- Evaluate the severity of anemia or polycythemia
- Monitor blood loss and blood transfusions
- Assess the effectiveness of treatments for certain blood disorders
- Screen for underlying medical conditions, such as dehydration or blood clotting disorders
Procedure
The hematocrit test involves the following steps:
- A blood sample is collected from a vein in the arm or from a finger prick
- The blood sample is placed in a centrifuge and spun at high speed to separate the different components of the blood
- The proportion of red blood cells in the blood is measured and expressed as a percentage of the total blood volume
Interpretation of Results
The normal range for hematocrit values varies depending on age, sex, and other factors:
- Newborns: 45-60%
- Infants: 35-55%
- Children: 35-50%
- Adult men: 40-54%
- Adult women: 37-48%
A low hematocrit value may indicate anemia, blood loss, or other conditions, while a high value may indicate polycythemia, dehydration, or other conditions.
Risks and Complications
The risks and complications associated with the hematocrit test are minimal and may include:
- Bleeding or bruising at the needle site
- Infection at the needle site
- Lightheadedness or dizziness due to blood loss
Preparation
No special preparation is required for the hematocrit test, but it is recommended to:
- Avoid eating or drinking for a few hours before the test
- Inform the healthcare provider of any medications or supplements being taken
Frequently Asked Questions (FAQs)
What is a hematocrit test?
Measures red blood cell percentage in blood.
Why is a hematocrit test done?
To diagnose anemia or blood loss.
How is a hematocrit test performed?
Blood sample taken from vein or finger prick.
What does the test measure?
Percentage of red blood cells in blood.
What is a normal hematocrit range?
40-54% for men, 37-48% for women.
What is a low hematocrit level indicative of?
Anemia or blood loss.
What is a high hematocrit level indicative of?
Dehydration or polycythemia.
Is fasting required before the test?
No, fasting not typically required.
Are there any risks associated with the test?
Minor bleeding or bruising at puncture site.
How long does it usually take to get results?
Usually within 1-2 hours or next day.
Article last updated on: 26th June 2025.
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