ESR- erythrocyte sedimentation rate

The Erythrocyte Sedimentation Rate (ESR) is a non-specific blood test that measures the rate at which red blood cells settle in a vertical tube over a specified period, usually one hour. It is an indirect measure of inflammation in the body.

During the test, anticoagulated blood is placed in a narrow tube, and the rate at which the red blood cells settle (sediment) is measured in millimeters per hour (mm/hr). The principle behind ESR is based on the fact that inflammatory proteins, such as fibrinogen and immunoglobulins, cause red blood cells to clump together and settle faster than normal. Higher levels of these proteins in the blood indicate increased inflammation.

ESR is influenced by various factors including age, sex, anemia, and certain medications. Normal ESR values differ by age and gender, with slightly higher rates in females. It is important to interpret ESR results in the context of a patient's overall clinical picture and other diagnostic tests

Clinically, ESR is used as a screening tool for a wide range of conditions associated with inflammation, such as infections, autoimmune diseases (like rheumatoid arthritis and lupus), certain cancers, and chronic inflammatory conditions. Changes in ESR over time can also help monitor disease activity and response to treatment.

However, ESR is not specific to any particular disease and can be influenced by non-inflammatory conditions as well. Therefore, it is often used in conjunction with other tests to aid in diagnosis and monitoring of diseases. Despite its limitations, ESR remains a valuable and widely used tool in clinical practice for assessing inflammatory status and guiding further investigations.