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:

  1. A blood sample is collected from a vein in the arm or from a finger prick
  2. The blood sample is placed in a centrifuge and spun at high speed to separate the different components of the blood
  3. 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:

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?
A blood test that measures the proportion of red blood cells in the blood.

Why is a Hematocrit test performed?
To diagnose and monitor conditions such as anemia, dehydration, and blood loss.

How is a Hematocrit test done?
A blood sample is taken from a vein or finger prick and spun in a centrifuge to separate the blood components.

What does the result of a Hematocrit test indicate?
The percentage of red blood cells in the blood, with normal ranges varying by age, sex, and other factors.

What are normal Hematocrit levels?
Typically around 40-54% for adult men and 37-48% for adult women, but can vary slightly depending on the laboratory.

How long does it usually take to get the results of a Hematocrit test?
Usually within a few hours to a day, depending on the laboratory and testing methods used.

Are there any risks or side effects associated with a Hematocrit test?
Generally minimal, but may include bruising, bleeding, or discomfort at the needle site.

Can a Hematocrit test be performed on people of all ages?
Yes, but normal ranges and testing methods may vary for infants, children, and older adults.

Is fasting required before a Hematocrit test?
Not typically required, but may be necessary in some cases depending on the laboratory or other tests being performed.

Can a Hematocrit test diagnose specific diseases or conditions?
It can help diagnose certain conditions, such as anemia, but often requires interpretation in conjunction with other test results and medical evaluation.

Article last updated on: 18th October 2025.
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