What it measures
The erythrocyte sedimentation rate (ESR) measures how far red blood cells settle in a tube of blood in one hour. Inflammation adds proteins to the blood that make the cells settle faster, so a high ESR is a general sign of inflammation, though it does not show where it is.
Why people test it
- Checked when inflammation is suspected but its cause is unclear.
- Used to look for and monitor certain conditions, such as giant cell arteritis and polymyalgia rheumatica.
- Monitored in long-term inflammatory conditions, often alongside CRP.
Typical range
Ranges vary between labs, with the method used, age and sex, and your report shows the lab's own range. ESR rises with age and is higher in women; one NHS lab gives 1 to 10 mm/hour for men and 1 to 12 mm/hour for women up to 50. Source: Newcastle Hospitals Laboratories: erythrocyte sedimentation rate.
Finger-prick or vein?
A vein draw is usually advised. The test needs a fuller tube of blood than a finger-prick gives, and the sample should reach the lab within hours.