Blood and lab tests
What Does ESR Mean on a Blood Test? Sed Rate Explained
ESR (Erythrocyte Sedimentation Rate) · say it: ee-ess-ARAlso written: sed rate, sedimentation rate, erythrocyte sedimentation rate
Short answer
ESR measures how fast red blood cells sink in a tube of blood over an hour; a faster rate can be a general sign of inflammation.
What it means
In this test, blood is placed in a tall, thin tube and the lab measures how far the red cells fall in one hour. When there is inflammation, certain proteins in the blood make red cells clump and sink faster.
ESR is a non-specific test. It can show that inflammation may be present, but not where it is or what is causing it. It is often used to help track some inflammatory conditions over time.
ESR naturally tends to be higher in older people, women and during pregnancy, and anaemia can also raise it. It changes more slowly than CRP, another inflammation marker.
Where you may see it
- Inflammation screening panels
- Monitoring of some joint and autoimmune conditions
- General blood test panels
📄 How it looks on a report
ESR 28 mm/hr H
🙅 What it does not mean
- A raised ESR does not identify a disease or where in the body a problem is.
- A normal ESR does not rule out every inflammatory condition.
- Age, sex, pregnancy and anaemia can all push ESR up without an inflammatory illness.
🗒️ Questions to ask your doctor
🧾 Reports where you will see “ESR (Erythrocyte Sedimentation Rate)”
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🔗 Read more from trusted sources
- “ESR (Erythrocyte Sedimentation Rate)” on MedlinePlus ↗
US National Library of Medicine
- NCI Dictionary definition ↗
US National Cancer Institute: “sedimentation rate”
- MedlinePlus lab test guides ↗
US National Library of Medicine
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