The sedimentation rate, also known as the erythrocyte sedimentation rate (ESR) or the sed rate, is a test that measures the speed at which red blood cells (erythrocytes) settle to the bottom of a tube in a blood sample. The sedimentation rate is typically used as a screening test to help diagnose inflammation in the body.
A higher sedimentation rate indicates that there is more inflammation present in the body. The sedimentation rate can be elevated due to various conditions, including infections, autoimmune disorders, cancer, and certain types of tissue damage. However, a high sedimentation rate does not provide information about the specific cause of the inflammation or the location of the inflammation in the body.
The sedimentation rate is typically measured using a simple blood test. A blood sample is collected and placed in a tube left to sit for a period of time. The distance that the red blood cells have settled after a certain amount of time is measured and used to calculate the sedimentation rate. The test results are usually reported in millimeters per hour (mm/hr).
It is important to note that the sedimentation rate is just one of many tests that may be used to diagnose and monitor inflammation in the body. It is often used in conjunction with other tests, such as a complete blood count (CBC) and blood tests that measure levels of specific proteins, to help diagnose the underlying cause of inflammation.