Erythrocyte Sedimentation Rate:- Part 2 – ESR Solution and Procedure
- Blood in EDTA or oxalate can be used.
Principle of ESR
- ESR test is based on the principle of sedimentation.
- When the blood in an anticoagulant is left, undisturbed RBCs will settle down in the container, or the Wintrobe tube marked 0 to 100 mm.
- This is the speed of sedimentation of red blood cells in plasma over a period of one hour.
- This is a nonspecific test but, when raised, has great significance.
- The best test to diagnose occult disease.
- Diagnose and monitor temporal arteritis.
- Diagnose and monitor the Polymyalgia rheumatica.
- Monitoring Hodgkin’s disease.
- Advanced Malignancies.
- In myocardial infarction, where it is raised while in angina is normal.
Factors influencing ESR
- Plasma protein
- In normal blood, RBCs suspended in the plasma form few aggregates of RBCs. So the rate of sedimentation is slow.
- If there is a rouleaux formation, that will give a false value. So acute phase protein affects the ESR.
- Number of RBCs
- ESR depends upon the number of RBCs, like in anemia decreased, the number of RBCs settles down rapidly.
- In the case of polycythemia, RBCs settle slowly, and ESR is low.
- Shape of RBCs
- Changes in the shape affect the ESR like in Sickle cell anemia, ESR may be low or zero.
- Size of the RBCs
- Macrocytes cells settle more rapidly than the microcytes because of their large size.
Technical factors affecting ESR, giving false increased value:
- False increased ESR sees in:
- Test when reading after one hour.
- When there is improper dilution with the anticoagulant.
- When the tube is not vertical and is tilted to one side.
- If there is a vibration of the tube during the test.
- If blood is not mixed properly or there are micro-clots.
- The test is done at room temperature >25 °C.
Technical factors affecting ESR and giving false lower value:
- When the test is read for less or more than one hour.
- Improper mixing of the blood.
- Improper dilution of the blood.
- If the blood temperature is low.
- If there are air bubbles in the tube.
- If the room temperature is <20 °C.
- Analytical balance.
- Trisodium citrate (analytical grade).
- Distal water.
Method to prepare ESR solution:
- Weigh 3.8-gram Trisodium citrate /100 mL of water.
- Suppose you are preparing 500 mL of ESR solution.
- Take 19 grams of Trisodium citrate.
- Dissolve in 500 mL of distal water.
- Mix thoroughly.
How to do ESR (Procedure):
- ESR should be done within 2 hours of the collection of the blood.
- Blood can be kept at 4 °C for 6 hours. Now bring the blood to room temperature.
- Take 0.2 mL of ESR solution + 1.8 mL of oxalate blood or blood in EDTA.
- Fill the Wintrobe ESR tube. (mix the blood thoroughly before filling the tube).
- Mount in the ESR stand.
- Start the clock for one hour.
- Record the result after one hour.
- That is the ratio of settled cells and above clear plasma.
- The temperature should be kept between 20 to 25 °C.
Automated Mini-Ves ESR:
- Automated Mini-Ves ESR measure in 20 minutes instead of one hour.
- This 20 minutes ESR reading correlates to the 1-hour Westergren method.
- 1mL of sample is drawn up into a solution of 0.109 mol/L sodium citrate.
- It is placed in the Mini-VES machine.
- This instrument record the reading via its optical assembly.
- The second reading is recorded after 20 minutes to give the ESR value.
|Child||0 to 10|
|<50 years||0 to 15||0 to 20|
|>50 years||0 to 20||0 to 30|
mm / hour. (Wintrobe method)
- < 50 years of age = 0 to 9 mm/hour.
- >50 years of age = 0 to 20 mm/hour.
- <50 years of age = 0 to 20 mm/hour.
- Children = 0 to 13 mm/hour.
Increased ESR Value:
- Increased plasma globulins.
- Increased plasma fibrinogen.
- Multiple myelomas.
- Acute and chronic inflammatory conditions.
- Autoimmune inflammatory diseases.
- Chronic renal failure.
- Cancers (malignant tumors).
Decreased ESR value:
- In the case of Sickle cell anemia.
- Increased plasma viscosity.
- NOTE: Please see more details on ESR in CBC.