Definition

Measures the time it takes for red blood cells to settle to the bottom of a tube. The faster the red blood cells clump together and settle, the more inflammation there is in the body.

Purpose

Ordered when there are signs of inflammatory disease: joint stiffness, unexplained fever, weight loss, headache, neck/shoulder pain, loss of appetite or anemia.

Results

A high ESR may point to inflammation associated with arthritis, vasculitis, kidney disease, infections, autoimmune diseases, heart disease or some cancers. A low ESR may suggest blood disorders such as polycythemia or sickle cell anemia, heart failure, or kidney/liver problems.

Normal Values

Laboratory-specific. Normal ESR levels vary by age and sex.

Risks and Limitations

Critical limitation: the ESR test alone cannot say what is causing the inflammation; it cannot diagnose a disease. Pregnancy, the menstrual cycle, aging, obesity, alcohol consumption, exercise, medications and supplements affect the result.

Related Tests

CRP (C-Reactive Protein)

CRP is a blood protein produced by the liver in response to inflammation. The test measures its level in the blood.

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Complete Blood Count (CBC)

A group of tests that measures the number and size of the cells in the blood. Red blood cells (erythrocytes), white blood cells (leukocytes), platelets, hemoglobin, hematocrit and

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RF (Rheumatoid Factor)

Detects a protein produced by the immune system that mistakenly attacks healthy antibodies (IgG) instead of germs. It is an autoimmune marker, not an indicator of infection.

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ANA (Antinuclear Antibody)

The immune system produces proteins called antibodies to fight foreign substances such as viruses and bacteria. Antinuclear antibodies, however, mistakenly target healthy cells.

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