ESR (Erythrocyte Sedimentation Rate)
The ESR (Erythrocyte Sedimentation Rate) is a common, non-specific blood test that measures the rate at which red blood cells (erythrocytes) settle to the bottom of a vertical tube of blood over a specific period, typically one hour.
This test is an indirect measure of the degree of inflammation present in the body. It does not diagnose a specific disease, but rather indicates that a disease process is present and causing inflammation.
How the ESR Test Works
- Principle: In a healthy person, red blood cells settle slowly.
- Inflammation's Effect: When inflammation is present, the body produces high levels of certain large proteins called acute phase reactants (such as fibrinogen and immunoglobulins).
- Aggregation: These proteins coat the red blood cells, causing them to clump together (aggregate) and form stacks called rouleaux.
- Faster Sedimentation: These heavier, clumped stacks fall through the plasma more quickly, resulting in a higher (faster) ESR rate.
