What this test measures
The ESR (Erythrocyte Sedimentation Rate) measures the speed at which red blood cells settle to the bottom of a thin vertical tube of anti-coagulated blood in one hour. The Westergren method is the international standard. Healthy RBCs settle slowly because their negative surface charge keeps them apart. In states of inflammation, infection, or malignancy, increased fibrinogen and immunoglobulins in plasma neutralise this charge and cause RBCs to stack ("rouleaux formation") and settle faster.
The test is simple, cheap, and very sensitive — but very non-specific. It rises in essentially any condition that increases acute-phase proteins. It is mainly used to (a) help decide whether vague symptoms warrant further investigation, and (b) monitor disease activity in known inflammatory conditions like rheumatoid arthritis, polymyalgia rheumatica, and giant cell arteritis.
Why it matters
For Indian outpatient practice, ESR remains a cheap and useful triage tool — a normal ESR in a patient with vague fatigue and aches significantly lowers the probability of major chronic inflammation. A very high ESR (>100 mm/hr) is unusual and narrows the differential sharply to a short list: multiple myeloma, temporal arteritis, polymyalgia rheumatica, deep-seated infection (endocarditis, TB, abscess), and metastatic cancer.
ESR is also a longitudinal marker — your doctor may track it over weeks or months to see whether disease activity is improving or worsening on treatment. CRP and hsCRP are faster acute-phase markers, but ESR remains useful for chronic conditions and is often ordered alongside.
How to prepare
No fasting required. ESR is affected by pregnancy, menstruation, age, sex, and severe anaemia — disclose these for context. The sample must be processed within a few hours of collection (Westergren tubes are set up in the lab).
Markers & reference ranges
Reference ranges below are typical adult values. Your lab's reported range may differ slightly based on the assay platform and patient demographics — always read your report against the range printed on it.
| Marker | Normal range | If low | If high |
|---|---|---|---|
| ESR (Westergren) (mm/hr)[1][2] | Men < 50y: <15 · Men > 50y: <20 · Women < 50y: <20 · Women > 50y: <30 · Children: <10 | A low ESR is generally unimportant. Occasionally seen with polycythaemia, sickle cell disease, severe leucocytosis, hypofibrinogenaemia, or congestive heart failure. | Mild rise (up to 40): minor infection, age, pregnancy, anaemia. Moderate rise (40–100): active inflammation, infection, autoimmune disease, anaemia. Very high (>100 mm/hr): multiple myeloma, temporal arteritis, polymyalgia rheumatica, TB, endocarditis, occult malignancy, severe sepsis. |
ESR ranges by age, sex, and pregnancy
| Group | Upper limit of normal (mm/hr) |
|---|---|
| Men < 50 years | 15 |
| Men > 50 years | 20 |
| Women < 50 years | 20 |
| Women > 50 years | 30 |
| Children | 10 |
| Pregnancy | Up to 45 (varies by trimester) |
Frequently asked questions
What does ESR tell my doctor?
It is a non-specific marker of inflammation. A high ESR says "something inflammatory is happening" but does not say what. A normal ESR makes major chronic inflammation less likely.
Do I need to fast?
No.
My ESR is 80 — what could be going on?
An ESR of 80 suggests moderate-to-marked inflammation. Common causes in Indian adults include TB, urinary tract infection, rheumatoid arthritis, lupus, anaemia, and (in older adults) polymyalgia rheumatica or malignancy. Your doctor will combine ESR with CBC, CRP, urine, and clinical findings to narrow the cause.
Why is ESR higher in older people?
ESR naturally rises with age — partly due to mild chronic inflammation, partly due to age-related changes in plasma proteins. The age-adjusted upper limit is roughly: men age/2; women (age+10)/2.
Is ESR or CRP better?
CRP rises faster (within 6 hours) and falls faster, so it is better for acute monitoring. ESR rises slowly (24–48 hours) and stays elevated longer, so it is useful for chronic conditions. They give complementary information.
Can ESR be normal with active disease?
Yes. ESR is a screen, not a definitive test. Active rheumatoid arthritis, malignancy, or chronic infection can occasionally have a normal ESR. Always interpret alongside symptoms and other tests.
How is ESR done?
Your blood is collected in a citrate tube, set up in a vertical Westergren tube, and the distance the red cells fall in one hour is measured in millimetres. Modern instruments automate this and report in minutes.
Will ESR detect cancer?
ESR is not a cancer screening test. However, very high ESR (>100) in someone without obvious infection or autoimmune disease can prompt cancer workup, especially in older patients.
Related Hematology / Anemia tests
Tests commonly ordered alongside ERYTHROCYTE SEDIMENTATION RATE (ESR), or that help interpret an unexpected result.
Sources & references
- NIH MedlinePlus — ESR Test · accessed 2026-05-30T00:00:00.000Z
- NCBI StatPearls — Erythrocyte Sedimentation Rate · accessed 2026-05-30T00:00:00.000Z
- American College of Physicians — Acute Phase Reactants · accessed 2026-05-30T00:00:00.000Z
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