ESR (erythrocyte sedimentation rate) measures the rate at which red blood cells settle to the bottom of a vertical tube over one hour. During inflammation, proteins like fibrinogen increase in the blood and cause red blood cells to clump together, making them settle faster.

ESR is a non-specific marker — it rises in many conditions including infection, autoimmune disease, cancer, pregnancy, and anemia. It is most useful as a screening tool and for monitoring known inflammatory conditions like rheumatoid arthritis, polymyalgia rheumatica, and temporal arteritis.

ESR increases naturally with age and tends to be higher in women. It is slower to respond than hsCRP (takes days to rise and weeks to normalize), making it better for tracking chronic inflammation rather than acute changes.

What It Measures

Rate at which red blood cells sediment in one hour, indirectly reflecting the degree of systemic inflammation.

Reference Ranges

How GATOR Tracks This

Related Biomarkers