What is this test?
ESR measures how quickly red blood cells settle in a tube over a set time. It is a broad marker that can change with inflammation, infection, anaemia, pregnancy, age and many other factors.
Why might it be ordered?
- To support investigation of persistent inflammatory symptoms.
- To follow the trend of an inflammatory condition alongside symptoms and other tests.
What sample is needed?
A blood sample is required. The laboratory chooses the correct tube and handles the sample for this test.
How should you prepare?
Fasting is usually unnecessary. Tell your clinician about pregnancy, recent illness and medicines that may affect interpretation.
How should you understand the result?
A raised ESR does not identify the cause or location of inflammation, and a normal ESR does not exclude disease. Trends and other findings are more informative than one value.
Sources and editorial status
This patient-facing text is an editorial draft. It should be approved by a laboratory physician before official publication.