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Erythrocyte Sedimentation Rate (ESR)

ESR — a blood test that measures the rate at which red blood cells settle, used to assess inflammation in the body.

A test that measures how far red blood cells settle in a tube within one hour. The value typically rises when there is inflammation, infection, or tissue damage in the body.

Indication

  • Investigation of unexplained fever, weight loss, or fatigue
  • Evaluation of rheumatoid arthritis and other autoimmune diseases
  • Suspected polymyalgia rheumatica and giant cell arteritis (temporal arteritis)
  • Inflammation monitoring during infectious diseases
  • Activity and treatment-response monitoring of known inflammatory diseases
  • Follow-up parameter in certain malignancies such as Hodgkin lymphoma
  • Diagnosis and follow-up of childhood rheumatic fever and Kawasaki disease

Preparation

  • No special preparation is required; fasting is not necessary
  • Inform the physician of medications used (steroids, NSAIDs, etc.)
  • Recent severe infection or surgery should be reported
  • Pregnancy must be reported because it affects results

How it's performed

  1. A venous blood sample is taken from the arm under sterile conditions (usually 2-3 mL)
  2. The blood is collected into a special citrated or EDTA tube
  3. Using the Westergren method, the amount of red cell sedimentation in an upright tube is measured in millimeters over one hour
  4. Results may be obtained more quickly with automated analyzers
  5. The result is reported in mm/hour

Post-procedure

  • Results are usually available the same day
  • Interpretation is performed in conjunction with clinical findings and other tests (CRP, complete blood count, etc.)
  • If treatment monitoring is required, the physician may repeat the test at specified intervals
  • Bruising at the venipuncture site is rare and resolves within a few days

Risks

  • Temporary pain or bruising at the venipuncture site
  • Rarely, a small hematoma may form
  • Dizziness or feeling faint due to needle phobia (rare)
  • Very rarely, local infection at the venipuncture site

FAQ

What is the normal ESR value?

Reference ranges are generally 0-15 mm/hour in adult men and 0-20 mm/hour in women. The upper normal limit may rise with age; interpretation is made according to age and the laboratory's reference range.

Does an elevated ESR always indicate a serious disease?

No. Older age, pregnancy, anemia, kidney disease, or mild infections can also raise the value. The result alone is not diagnostic; it is interpreted alongside clinical evaluation.

What is the difference between CRP and ESR?

CRP responds to inflammation more rapidly and returns to normal more quickly. ESR changes more slowly but is valuable for monitoring ongoing inflammation; the two tests are often used together.

Can I eat before the test?

Yes, the ESR test does not require fasting. If other tests are also requested from the same blood sample, you may need to follow the fasting rules required for those tests.