Sed Rate by Modified Westergren (Erythrocyte Sedimentation Rate - ESR)

The Sed Rate by Modified Westergren test, also known as the Erythrocyte Sedimentation Rate (ESR), measures how quickly red blood cells (erythrocytes) settle at the bottom of a test tube over one hour. It is a nonspecific test used to detect inflammation associated with infections, autoimmune diseases, and chronic illnesses.

1. What Is ESR?

• ESR is an indirect measure of the presence of inflammation in the body.

• When inflammation is present, certain proteins (e.g., fibrinogen) cause red blood cells to clump and settle faster.

• The Westergren method is the standardized and most widely used technique for measuring ESR.

2. Why Is the ESR Test Performed?

This test is used to:

• Detect inflammation associated with infections, autoimmune diseases, or cancers.

• Monitor the progression or response to treatment of chronic inflammatory conditions like rheumatoid arthritis or lupus.

• Assist in diagnosing temporal arteritis or polymyalgia rheumatica.

3. ESR Reference Ranges

• Men under 50: < 15 mm/hr

• Women under 50: < 20 mm/hr

• Men over 50: < 20 mm/hr

• Women over 50: < 30 mm/hr

• Reference ranges can vary with age, sex, and laboratory technique.

4. How to Interpret ESR Results

🔹 Elevated ESR:

• Suggests the presence of inflammation, infection, autoimmune disease, or certain cancers.

• Often seen in conditions such as rheumatoid arthritis, lupus, tuberculosis, and chronic kidney disease.

🔹 Normal ESR:

• Generally indicates absence of significant inflammation.

• May still be normal in early stages of disease or in conditions with low inflammatory markers.

🔹 Low ESR:

• May be seen in conditions like sickle cell disease, polycythemia, or extreme leukocytosis.

5. What Can Affect ESR Levels?

• Age and sex (ESR increases with age and is typically higher in women)

• Anemia (can raise ESR)

• Pregnancy or menstruation

• Certain medications (e.g., corticosteroids, statins)

• Technical issues with sample collection

6. How Is the Test Performed?

• A blood sample is drawn from a vein and placed in a tall, thin tube to measure how far red blood cells fall in one hour.

• No fasting or special preparation is typically required.

7. When to See a Doctor

🚨 Consult your healthcare provider if you:

• Have symptoms of inflammation (e.g., joint pain, fatigue, unexplained fevers).

• Are being monitored for a chronic inflammatory or autoimmune disease.

• Have persistently high ESR levels without a known cause.

🔹 Key Takeaways

✅ ESR is a nonspecific but useful marker for detecting and monitoring inflammation.

✅ Elevated levels suggest inflammation but do not identify the exact cause.

✅ The test is most useful when interpreted alongside other clinical findings and laboratory results.