01/08/2025
Erythrocyte Sedimentation Rate (ESR) Test
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1. Objective:
The objective of the ESR test was to measure the rate at which red blood cells (erythrocytes) settled at the bottom of a vertical tube in one hour, serving as a nonspecific marker of inflammation.
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2. Principle:
The test was based on the principle that during inflammation, certain proteins (like fibrinogen) cause RBCs to stick together and form rouleaux, which settle faster. The ESR value increased with inflammation or infection.
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3. Materials:
Fresh anticoagulated blood (EDTA or sodium citrate)
Westergren pipette or Wintrobe tube
ESR stand
Timer
Anticoagulant (for Westergren: 3.8% sodium citrate)
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4. Procedure (Microscopic not required – macroscopic):
(Using the Westergren method):
1. Blood was mixed with sodium citrate in a 4:1 ratio.
2. The Westergren tube was filled up to the 0 mark with the mixture.
3. The tube was placed vertically in an ESR stand, undisturbed, at room temperature.
4. After 1 hour, the height (in mm) of the clear plasma above the red cell column was read as the ESR.
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5. Result:
Normal range:
Men: 0–15 mm/hour
Women: 0–20 mm/hour
Increased ESR:
Infections, autoimmune diseases (e.g., rheumatoid arthritis), TB, anemia, malignancy
Decreased ESR:
Polycythemia, sickle cell anemia, leukocytosis
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6. Uses:
Helped detect and monitor inflammation, infection, or autoimmune diseases
Used to monitor disease progression or response to therapy
Often used alongside CRP (C-reactive protein) for better inflammatory assessment
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7. Consultation:
A physician interpreted ESR results with patient history, physical exam, and other tests. A raised ESR prompted further investigation into possible underlying conditions.
