Red Blood Cell Count

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Also known as: RBC count

At a Glance

Why Get Tested?

To evaluate any change in the number of red blood cells in your blood

When to Get Tested?

As part of a full blood count (FBC), which may be requested for a variety of reasons.

Sample Required?

A blood sample taken from a vein in your arm or by a finger-prick (children and adults) or heel-prick (newborns)

Test Preparation Needed?

None

The Test Sample

What is being tested?

This test counts the number of red blood cells (RBC) in a litre of blood. Red blood cells, which are made in the bone marrow, carry oxygen from the lungs to the cells and transport carbon dioxide from the cells to the lungs. Women tend to have lower RBC counts than men, and levels tend to decrease with age. When the value decreases by more than 10% of the expected normal value, the patient is said to be anaemic.

How is the sample collected for testing?

The test is performed on a blood sample taken by a needle placed in a vein in the arm or by a finger-prick (for children and adults) or heel-prick (for newborns).

NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.

Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.

Is any test preparation needed to ensure the quality of the sample?

No test preparation is needed.

The Test

Common Questions

Ask a Laboratory Scientist

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NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used.