ESR in a blood test stands for Erythrocyte Sedimentation Rate. It is a simple blood test that measures how quickly red blood cells (erythrocytes) settle at the bottom of a test tube over a period of one hour

. The test indirectly indicates the presence of inflammation in the body. When inflammation occurs, certain proteins increase in the blood, causing red blood cells to clump together and settle faster than normal. A higher ESR suggests more inflammation or an active disease process

. ESR is used to help detect conditions associated with inflammation such as infections, autoimmune diseases, and some cancers. It is not specific to any one disease and is usually done alongside other tests to determine the cause and location of inflammation

. It can also be used to monitor the effectiveness of treatment for inflammatory conditions like rheumatoid arthritis or temporal arteritis

. No special preparation is needed for the ESR test, and it is performed by drawing blood from a vein, typically in the arm

. In summary:

• ESR measures the rate at which red blood cells settle in blood.
• A high ESR indicates inflammation or disease activity.
• It is a non-specific test used with other diagnostics.
• Common uses include detecting and monitoring inflammatory diseases