FaridabadBy Dr B.C. Gupta, MD · 2026-08-15
An ESR test, or erythrocyte sedimentation rate, measures how quickly red blood cells settle at the bottom of a tube of blood. It is a simple test that can indicate the presence of inflammation in the body.
What does the test measure?
When there is inflammation, certain proteins in the blood make red cells clump together and settle faster. The ESR test measures this settling rate in millimetres per hour. A faster rate suggests more inflammation, though it does not say where the inflammation is or what is causing it.
How to prepare
No special preparation is needed. You do not need to fast. The sample is a blood draw, and the result is usually available the same day.
What a high result can mean
A high ESR can be a sign of inflammation from many causes, including infection, autoimmune conditions, or injury. It can also be raised in pregnancy, with anaemia, or with age. A normal ESR does not rule out inflammation. Because ESR is non-specific, it is usually read alongside other tests and your symptoms rather than on its own.
When is it ordered?
Doctors order an ESR to help investigate symptoms such as unexplained fever, joint pain, or fatigue, to monitor conditions that cause inflammation, or to check how well treatment is working. It is often done together with a CBC.
This article is for general information only and is not medical advice. Always discuss your results and any health concerns with your doctor.
