Hematology

Erythrocyte Sedimentation Rate

April 02, 2025 by Olivia R

Have you ever wondered why your doctor ordered you to have your erythrocyte sedimentation rate checked?

And why it is important?

Then what is an Erythrocyte Sedimentation Rate (ESR) test

Erythrocyte sedimentation rate (ESR) examination is a blood examination procedure that is carried out by measuring the time it takes for red blood cells to settle and clot at the bottom of a test tube.

The main purpose of conducting an erythrocyte sedimentation rate examination is to identify the presence of inflammation or inflammation in the body.

Purpose of an Erythrocyte Sedimentation Rate Examination

The purpose of an erythrocyte sedimentation rate test is to identify inflammation or inflammation in the body. Through this examination procedure, doctors can determine the severity of inflammation in the body. This is because when inflammation occurs, the body will produce proteins that cause red blood cells to clot easily

In addition, the erythrocyte sedimentation rate examination can also be used to evaluate the effectiveness of treatment and help confirm the diagnosis of several medical conditions, such as infections, rheumatoid arthritis, lupus, giant cell arteritis, polymyalgia rheumatica, and cancer.

Conditions That Require an Erythrocyte Sedimentation Rate Examination

Generally, doctors will recommend an erythrocyte sedimentation rate test if the patient experiences several conditions such as the following

1. Fever
2. Shoulder, neck, and pelvic pain
3. Headaches, especially if associated with shoulder pain
4. Joint pain that lasts for more than 30 minutes every morning
5. Rapid and drastic weight loss for no apparent reason
6. Decreased or loss of appetite
7. Digestive disorders, such as bloody stools, diarrhea, or abdominal pain that does not go away
8. Chronic headaches

It should be noted that the erythrocyte sedimentation rate test cannot indicate the location or part of the body that is experiencing inflammation. Therefore, doctors usually advise patients to undergo additional examination procedures, such as C-reactive protein (CRP), blood viscosity tests, or imaging procedures (CT scans, MRIs, and X-rays).

Principle of Work Erythrocyte Sedimentation Rate

Basically Erythrocyte Sedimentation Rate (ESR) measures how quickly red blood cells (RBCs) settle at the bottom of a tube in one hour. It is a non-specific test used to detect inflammation or infection in the body.

Erythrocytes are naturally denser than plasma, so they will settle due to gravity. Stokes' Law explains that the rate of sedimentation is influenced by

1. Erythrocyte size & aggregation (redded erythrocytes/rouleaux settle faster)
2. Plasma viscosity (thin plasma=higher ESR)
3. Difference in density between erythrocytes and plasma

When inflammation occurs, the liver produces acute proteins such as:

1. Fibrinogen
2. Globulin (eg: CRP, Immnunoglobulins)
3. This protein reduces the negative charge (zeta potential) on erythrocytes, so that
4. Erythrocytes easily form rouleaux (like coin stacks)
5. Erythrocyte aggregation accelerates sedimentation

Blood is mixed with an anticoagulant (eg: sodium citrate or EDTA) to prevent clotting.

1. Blood is put into a special tube (Westergren/Wintrobe)
2. Left for 1 hour in an upright position
3. The results are read as the sediment distance (mm) in 1 hour

How to perform erythrocyte sedimentation rate

Erythrocyte sedimentation rate test is a measure of the speed of sedimentation of erythrocyte cells in plasma. The unit is mm/hour. The examination method recommended by the International Committee for Standardization in Hematology (ICSH) is the Westergren method.

Erythrocyte Sedimentation Rate (ESR) Examination by Westergren Method

1. Patient Preparation: no special preparation is required
2. Sample preparation: Venous blood is mixed with 0.109 M Sodium Citrate solution anticoagulant with a ratio of 4:1. EDTA blood can also be used which is diluted with 0.109 M sodium citrate solution or 0.9% NaCl with a ratio of 4:1
3. Principle: measuring the speed of sedimentation of erythrocyte cells in plasma. The unit is mm/hour
4. Tools and materials:
1. Westergren pipette
2. Rack for Westergren pipette
3. Sodium citrate 0.109 M

1. Fill the Westergren pipette with diluted blood up to the 0 mark. The pipette must be clean and dry
2. Place the pipette on the rack and make sure that its position is completely perpendicular at a temperature of 18-250C. Keep away from sunlight and vibrations
3. After exactly 1 hour, read the results in mm/hour

Reference Values:

1. Male: 0-20 mm/hour
2. Female: 0-15 mm/hour

Erythrocyte Sedimentation Rate (ESR) Examination Wintrobe Method

1. Patient Preparation: no special preparation required
2. Sample Preparation: EDTA Blood
3. Principle: measuring the sedimentation rate of erythrocyte cells in plasma. The unit is mm/hour
4. Tools and materials:
• Wintrobe tube
• Capilary Pipette

1. Mix the contents of the specimen well so that it is homogeneous
2. Fill the Wintrobe tube with a capillary pipette to the 0 mark
3. Place the tube on the rack in a perpendicular position
4. Leave it for 1 hour. After exactly 1 hour, record the decrease in erythrocytes in mm/hour

Reference Values:

1. Male: 0-20 mm/hour
2. Female: 0-15 mm/hour

Factors Affecting Erythrocyte Sedimentation Rate (ESR)