Erythrocyte Sedimentation Rate
ESR· also: Sed Rate, Erythrocyte Sedimentation Rate
Clinical Overview
ESR measures how quickly red blood cells settle to the bottom of a test tube over one hour. When inflammation is present, proteins like fibrinogen coat red cells, causing them to clump and settle faster. ESR is a nonspecific marker of inflammation used to screen for and monitor inflammatory conditions.
Why This Test Matters
ESR is most useful for diagnosing and monitoring giant cell arteritis (temporal arteritis), polymyalgia rheumatica, and multiple myeloma — all of which cause dramatically elevated ESR. It is also used alongside CRP to monitor treatment response in rheumatoid arthritis and inflammatory bowel disease. A very high ESR (>100 mm/hr) has a narrow differential: infection, malignancy, or autoimmune disease.
Reference RangesWHO/IFCC standards
| Age Group | Sex | Reference Range | Unit | Notes |
|---|---|---|---|---|
| Adults (18–64) | Male | 0 – 15 | mm/hr | Westergren method; rises with age |
| Adults (18–64) | Female | 0 – 20 | mm/hr | — |
| Elderly (65+) | Male | 0 – 20 | mm/hr | Age >50 |
| Elderly (65+) | Female | 0 – 30 | mm/hr | Age >50 |
What Causes Abnormal Results?
High ESR Causes
- Bacterial infections (septicemia, TB, osteomyelitis)
- Autoimmune diseases (rheumatoid arthritis, lupus, vasculitis)
- Giant cell arteritis (often >100 mm/hr)
- Multiple myeloma and other paraproteinemias
- Malignancy
- Pregnancy and anemia
- Nephrotic syndrome
Low ESR Causes
- Polycythemia vera (too many cells, slower settling)
- Sickle cell disease (abnormal cell shape)
- Technical error (sample too old or tube tilted)
Signs & Symptoms to Watch For
How to Prepare for This Test
Blood should be tested within 2 hours of collection or refrigerated. No fasting required. Inform your doctor of any anti-inflammatory medications.
Factors That Can Affect Results
- Anemia (falsely raises ESR)
- Polycythemia (falsely lowers ESR)
- Pregnancy (physiologically elevated)
- Age (ESR rises normally with age)
- Technical factors: tube tilt, temperature, delay in testing
Related Topics
Frequently Asked Questions
What is the difference between ESR and CRP?
Both are inflammation markers but they behave differently. CRP rises and falls within hours of inflammation onset, making it better for detecting acute changes and monitoring treatment response. ESR rises over days and remains elevated longer, making it useful for chronic conditions. CRP is more sensitive and specific; ESR is simpler and cheaper. In clinical practice, both are often ordered together.
What ESR level is suspicious for multiple myeloma?
An ESR above 100 mm/hr without obvious infection or inflammatory disease should prompt investigation for multiple myeloma, which causes extreme elevation due to high circulating paraprotein. Serum protein electrophoresis (SPEP), urine Bence Jones protein, and bone marrow biopsy are the next diagnostic steps.