Lab test
ESR Test – Erythrocyte Sedimentation Rate Test
This page explains the esr test – erythrocyte sedimentation rate test, what it measures, and how to order it. The ESR test measures how quickly red blood cells settle at the bottom of a test tube, helping to detect inflammation in the body.
What this test is
The erythrocyte sedimentation rate (ESR) test is a blood test that assesses the rate at which red blood cells settle in a tube over a period of time. This rate can indicate the presence of inflammation in the body. It is often used as a non-specific marker to help evaluate various conditions.
What it measures
- Erythrocyte Sedimentation Rate — reflects the presence of inflammation
What the test involves
A healthcare professional will collect a blood sample from a vein in your arm using a needle. This is a standard blood draw procedure.
Why it is often ordered
Clinicians typically order an ESR test to help detect inflammation associated with conditions such as infections, autoimmune diseases, and some cancers. It can also be used to monitor the progress of an inflammatory disease or the effectiveness of treatment.
Preparation
No special preparation is usually needed for the ESR test, but it's important to follow any specific instructions provided by the lab.
How results are reported
Results are reported as the rate at which red blood cells settle in a tube, usually in millimeters per hour. Reference ranges can vary by laboratory, so consult with your healthcare provider for interpretation.
Before you go
- Turnaround time for results
- Specific preparation instructions
- Lab's reference range for results
FAQ
Frequently asked questions
What conditions can an ESR test help detect?
An ESR test can help detect conditions that cause inflammation, such as infections, autoimmune diseases, and some types of cancer. It is a general marker and not specific to any one condition.
Is fasting required before an ESR test?
Fasting is not typically required before an ESR test. However, it's important to follow any instructions given by your healthcare provider or the lab.
How is an ESR test different from a CRP test?
Both ESR and CRP tests measure inflammation, but they do so in different ways. ESR measures the rate of red blood cell sedimentation, while CRP measures the level of C-reactive protein in the blood.
Can medications affect ESR test results?
Yes, certain medications can affect ESR results. It's important to inform your healthcare provider about any medications you are taking before the test.
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