What is the primary purpose of the erythrocyte sedimentation rate (ESR) test?

The primary purpose of the erythrocyte sedimentation rate (ESR) test is to detect infections or inflammation in the body. The ESR measures how quickly red blood cells (erythrocytes) settle to the bottom of a test tube filled with blood. Under normal circumstances, red blood cells settle slowly. However, in the presence of inflammatory processes, certain proteins produced by the liver increase in the blood, causing the red blood cells to clump together and settle more quickly. Therefore, a higher ESR can indicate conditions such as infections, autoimmune diseases, and other inflammatory disorders.

This test is a non-specific marker, meaning it does not point to a specific disease but rather signals that further investigation is warranted to identify the underlying cause of the inflammation or infection. The ability of the ESR to reflect the presence of these conditions makes it a valuable tool in clinical practice.