22/07/2025
Erythrocyte Sedimentation Rate (ESR) Test
1. Objective
The objective of the ESR test was to measure the rate at which red blood cells (RBCs) settled at the bottom of a vertical tube in a given time period (usually 1 hour), to assess the presence of inflammation or infection in the body.
2. Principle
The ESR test was based on the principle that inflammatory processes caused red blood cells to clump together (rouleaux formation), increasing their sedimentation rate.
• The greater the inflammation, the faster the RBCs settled.
• The distance (in mm) that RBCs fell in a vertical tube over 1 hour indicated the ESR value.
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3. Materials
• Fresh anticoagulated blood (with EDTA or sodium citrate)
• Westergren ESR tube (200 mm long)
• Westergren pipette stand or ESR rack
• Timer or stopwatch
• Gloves
• Syringe or pipette
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4. Procedure (Macroscopic)
1. 1 part of 3.8% sodium citrate was mixed with 4 parts of blood.
2. The mixture was drawn into a Westergren tube up to the 0 mark.
3. The tube was placed vertically in an ESR rack.
4. After exactly 1 hour, the level of plasma above the RBC column was recorded in millimeters.
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5. Result
• ESR was recorded in mm/hr.
• Normal Range:
o Males: 0–15 mm/hr
o Females: 0–20 mm/hr
o Children: 0–10 mm/hr
o Elderly: Slightly higher
• Elevated ESR indicated inflammation, infection, autoimmune disorders, or malignancy.
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6. Uses
• Used as a non-specific marker of inflammation.
• Helped monitor disease progression or treatment effectiveness in conditions like:
o Rheumatoid arthritis
o Tuberculosis
o Temporal arteritis
o Chronic infections
• Also used in diagnosing autoimmune diseases and certain cancers.
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7. Consultation
• ESR results were interpreted alongside clinical symptoms and other laboratory findings.
• A high ESR alone did not confirm a diagnosis but prompted further investigations.
• Physicians used ESR to monitor chronic conditions and determine disease activity.
