Erythrocyte Sedimentation Rate (ESR): Principle, Procedure and Interpretation
The ESR explained: its principle, the standard Westergren procedure, reference ranges by age and sex, and the clinical situations where it changes your assessment.
The Erythrocyte Sedimentation Rate (ESR) is one of the oldest laboratory tests still in routine use. It is non-specific, inexpensive, and remarkably useful when read correctly. ESR measures how fast red blood cells settle in a vertical column of anticoagulated blood over one hour — an indirect marker of acute-phase proteins, principally fibrinogen and immunoglobulins.
Because ESR is non-specific, its power lies in interpretation rather than diagnosis. This guide covers the principle, the standard Westergren procedure, reference ranges, and the clinical situations where ESR changes your thinking.
Objective of the Test
- •Detect and monitor non-specific inflammation.
- •Support the diagnosis of polymyalgia rheumatica and giant cell arteritis.
- •Monitor disease activity in rheumatoid arthritis and other connective tissue diseases.
- •Support the diagnosis of osteomyelitis, tuberculosis, and some malignancies.
Principle
When anticoagulated blood stands in a vertical tube, red cells aggregate and sediment. The speed of sedimentation depends on the balance between factors that promote aggregation (fibrinogen, globulins, acute-phase proteins) and factors that oppose it (red cell surface charge, haematocrit).
Aggregation is increased by fibrinogen, immunoglobulins, and rouleaux formation, and decreased by low fibrinogen, low globulins, and the normal negative charge (zeta potential) of red cells. A high ESR therefore reflects a shift in plasma proteins toward the acute-phase pattern, not a disease in itself.
Equipment
- •Westergren ESR tubes (200 mm, internal diameter 2.55 mm)
- •ESR stand or automated ESR analyser
- •Disposable citrate tubes for automated methods
- •Timer and a level bench surface
Sample Type and Preparation
| Item | Requirement |
|---|---|
| Item | Requirement |
| Sample type | Venous blood in EDTA (manual) or citrate (automated) |
| Anticoagulant | EDTA for Westergren; sodium citrate 3.8% for automated |
| Timing | Perform within 4 hours of collection; keep at room temperature |
| Volume | Fills tube to the marked line — dilution ratio is critical |
Procedure (Manual Westergren)
| Step | Action |
|---|---|
| Step | Action |
| 1 | Mix the EDTA sample gently by inversion 8–10 times |
| 2 | Withdraw blood into the Westergren tube exactly to the 0 mark |
| 3 | Place the tube vertically in the stand — no tilt, no vibration |
| 4 | Leave undisturbed at room temperature for exactly 60 minutes |
| 5 | Read the height of the clear plasma column above the red cells in mm |
| 6 | Report as mm/hour; repeat in duplicate for critical results |
Result Interpretation
| ESR (mm/h) | Interpretation |
|---|---|
| ESR (mm/h) | Interpretation |
| < 15 (men), < 20 (women) | Normal |
| 20–40 | Mild elevation — infection, mild inflammation, anaemia |
| 40–70 | Moderate elevation — active inflammatory disease, tuberculosis |
| 70–100 | Marked elevation — giant cell arteritis, myeloma, malignancy, severe infection |
| > 100 | Suggests serious systemic disease — investigate urgently |
Always interpret alongside CRP — the two are complementary. CRP rises and falls faster; ESR changes more slowly.
Normal Ranges and Units
| Group | Reference Range |
|---|---|
| Group | Reference Range |
| Men | 0–15 mm/hour |
| Women | 0–20 mm/hour |
| > 50 years | Add age ÷ 2 to the upper limit |
| Children | 0–10 mm/hour |
Final Comment
ESR is a screening test. A normal ESR does not exclude disease, and an elevated ESR does not confirm one. Its greatest value is in longitudinal monitoring — a rising ESR in a patient with known inflammatory disease is often more informative than a single high value at presentation.
Scientific Correlations with Disease
- •Giant cell arteritis — ESR often > 100 mm/h; a normal ESR makes the diagnosis unlikely but does not exclude it.
- •Polymyalgia rheumatica — marked ESR elevation with proximal muscle pain and stiffness.
- •Tuberculosis and osteomyelitis — moderate to marked elevation; useful for monitoring response to treatment.
- •Myeloma — very high ESR due to rouleaux formation from paraproteins.
- •Anaemia — lowers haematocrit and falsely raises ESR; correct interpretation is needed.
Found this helpful? Share it with colleagues, or connect with me on LinkedIn for more lab medicine content.
Dr. Mohammad Sulieman — Medical Laboratory Specialist & Academic Lecturer
Comments
Comments are moderated
❤️ Likes are instant for everyone! 💬 Comments are reviewed by our team before being published. Please use only letters, numbers, and basic punctuation.
No comments yet. Be the first to share your thoughts!
Related Articles
Mohammad Sulieman Ibrahim
Full Stack Developer & Writer
Erythrocyte Sedimentation Rate (ESR): Principle, Procedure and Interpretation
By Mohammad Sulieman
https://medblog.seeha.tech/posts/sraa-trsyb-alkryat-alhmraaa-esr-almbda-oalagraaa-oaltfsyr
Scan to read online
The Erythrocyte Sedimentation Rate (ESR) is one of the oldest laboratory tests still in routine use. It is non-specific, inexpensive, and remarkably useful when read correctly. ESR measures how fast red blood cells settle in a vertical column of anticoagulated blood over one hour — an indirect marker of acute-phase proteins, principally fibrinogen and immunoglobulins.
Because ESR is non-specific, its power lies in interpretation rather than diagnosis. This guide covers the principle, the standard Westergren procedure, reference ranges, and the clinical situations where ESR changes your thinking.
Objective of the Test
- •Detect and monitor non-specific inflammation.
- •Support the diagnosis of polymyalgia rheumatica and giant cell arteritis.
- •Monitor disease activity in rheumatoid arthritis and other connective tissue diseases.
- •Support the diagnosis of osteomyelitis, tuberculosis, and some malignancies.
Principle
When anticoagulated blood stands in a vertical tube, red cells aggregate and sediment. The speed of sedimentation depends on the balance between factors that promote aggregation (fibrinogen, globulins, acute-phase proteins) and factors that oppose it (red cell surface charge, haematocrit).
Aggregation is increased by fibrinogen, immunoglobulins, and rouleaux formation, and decreased by low fibrinogen, low globulins, and the normal negative charge (zeta potential) of red cells. A high ESR therefore reflects a shift in plasma proteins toward the acute-phase pattern, not a disease in itself.
Equipment
- •Westergren ESR tubes (200 mm, internal diameter 2.55 mm)
- •ESR stand or automated ESR analyser
- •Disposable citrate tubes for automated methods
- •Timer and a level bench surface
Sample Type and Preparation
| Item | Requirement |
|---|---|
| Item | Requirement |
| Sample type | Venous blood in EDTA (manual) or citrate (automated) |
| Anticoagulant | EDTA for Westergren; sodium citrate 3.8% for automated |
| Timing | Perform within 4 hours of collection; keep at room temperature |
| Volume | Fills tube to the marked line — dilution ratio is critical |
Procedure (Manual Westergren)
| Step | Action |
|---|---|
| Step | Action |
| 1 | Mix the EDTA sample gently by inversion 8–10 times |
| 2 | Withdraw blood into the Westergren tube exactly to the 0 mark |
| 3 | Place the tube vertically in the stand — no tilt, no vibration |
| 4 | Leave undisturbed at room temperature for exactly 60 minutes |
| 5 | Read the height of the clear plasma column above the red cells in mm |
| 6 | Report as mm/hour; repeat in duplicate for critical results |
Result Interpretation
| ESR (mm/h) | Interpretation |
|---|---|
| ESR (mm/h) | Interpretation |
| < 15 (men), < 20 (women) | Normal |
| 20–40 | Mild elevation — infection, mild inflammation, anaemia |
| 40–70 | Moderate elevation — active inflammatory disease, tuberculosis |
| 70–100 | Marked elevation — giant cell arteritis, myeloma, malignancy, severe infection |
| > 100 | Suggests serious systemic disease — investigate urgently |
Always interpret alongside CRP — the two are complementary. CRP rises and falls faster; ESR changes more slowly.
Normal Ranges and Units
| Group | Reference Range |
|---|---|
| Group | Reference Range |
| Men | 0–15 mm/hour |
| Women | 0–20 mm/hour |
| > 50 years | Add age ÷ 2 to the upper limit |
| Children | 0–10 mm/hour |
Final Comment
ESR is a screening test. A normal ESR does not exclude disease, and an elevated ESR does not confirm one. Its greatest value is in longitudinal monitoring — a rising ESR in a patient with known inflammatory disease is often more informative than a single high value at presentation.
Scientific Correlations with Disease
- •Giant cell arteritis — ESR often > 100 mm/h; a normal ESR makes the diagnosis unlikely but does not exclude it.
- •Polymyalgia rheumatica — marked ESR elevation with proximal muscle pain and stiffness.
- •Tuberculosis and osteomyelitis — moderate to marked elevation; useful for monitoring response to treatment.
- •Myeloma — very high ESR due to rouleaux formation from paraproteins.
- •Anaemia — lowers haematocrit and falsely raises ESR; correct interpretation is needed.
Found this helpful? Share it with colleagues, or connect with me on LinkedIn for more lab medicine content.
Dr. Mohammad Sulieman — Medical Laboratory Specialist & Academic Lecturer
Did you find this helpful?
I am Mohammad Sulieman, a Full Stack Developer & Writer. Let's connect and build something amazing together.