Quick Guide: Erythrocyte sedimentation rate (ESR) Blood Test
What it is: An ESR (erythrocyte sedimentation rate) test, or "sed rate," measures how quickly red blood cells settle to the bottom of a test tube over one hour as a general marker of inflammation.
Why it's ordered: Ordered to help detect or monitor inflammatory conditions such as rheumatoid arthritis, other autoimmune diseases, or infections, often alongside CRP.
What it detects: Inflammation increases certain blood proteins that cause red blood cells to clump and settle faster. ESR doesn't identify where or why inflammation is occurring — it's a nonspecific signal used to screen for or track inflammatory activity over time.
Collection & prep: A standard blood draw from a vein in the arm. No special preparation is required.
Results:
High – suggests inflammation somewhere in the body; can also rise with age, infection, or other non-inflammatory conditions
Normal – roughly 0–20 mm/hr in men and 0–30 mm/hr in women, varying by age and lab
Possible complications: ESR can't confirm or rule out a specific condition on its own; it's most useful for tracking inflammation over time and is typically interpreted alongside symptoms and other tests like CRP.
Statements made in the Clinical Manual have not been evaluated by the FDA. The products mentioned are not intended to diagnose, treat, cure or prevent any disease.
