Erythrocyte Sedimentation Rate Notes

Erythrocyte Sedimentation Rate Definition

• Erythrocyte Sedimentation Rate (ESR) is the rate at which the erythrocytes settle down.
• Normally, the RBCs remain suspended uniformly in circulation. This is called suspension stability of RBCs.
• If blood is mixed with an anticoagulant and allowed to stand on a vertical tube, the red cells settle down due to gravity with a supernatant layer of clear plasma.
• ESR is also called sedimentation rate, sed rate or Biernacki reaction. It was first demonstrated by Edmund Biernacki in 1897.

Read And Learn More: Medical Physiology Notes

Determination Of ESR

There are two methods to determine ESR.

1. Westergren’s method
2. Wint robe’s method

1. Westergren’s Method: In this method, Westergren’s tube is used to determine ESR.

• 1.6 mL of blood is mixed with 0.4 mL of 3.8 percent sodium citrate (anticoagulant) and loaded in Westergren’s tube.
• The ratio of blood and anticoagulant is 4:1. The tube is fitted to the stand vertically and left undisturbed. The reading is taken at the end of 1 hour.

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2. Wintrobe’s Method: In this method, Wintrobe’s tube is used to determine ESR.

Wint robe’s Tube:

• Wintrobe’s tube is a short tube opened on only one end. It is 110 mm long with 3 mm bore.
• Wintrobe’s tube is used for determining ESR and PCV. It is marked on both sides. On one side the marking is from 0 to 100 (for ESR) and on other side from 100 to 0 (for PCV).
• About one mL of blood is mixed with an anticoagulant, EDTA. The blood is loaded in the tube up to ‘0’ mark and the tube is placed on the Wintrobe’s stand. And, the reading is taken after one hour.

Normal Values

Normal Values Of ESR

By Westergren’s Method

• In males: 3 to 7 mm in one hour
• In females: 5 to 9 mm in one hour
• Infants: 0 to 2 mm in one hour

By Wint robe’s Method

• In males: 0 to 9 mm in one hour
• In females: 0 to 15 mm in one hour
• Infants: 0 to 5 mm in one hour

Variations Of ESR

Physiological Variation

• Age: ESR is less in children and infants because of more number of RBCs
• Sex: It is more in females than in males because of less number of RBCs
• Menstruation: The ESR increases during menstruation 5. RBC count: When RBC count increases, the because of loss of blood and RBCs
• Pregnancy: From 3rd month to parturition, ESR increases up to 35 mm in one hour because of hemodilution.

Pathological Variation:

ESR increases in diseases such as

1. Tuberculosis
2. All types of anemia except the sickle cell anemia 3. Malignant tumors
3. Rheumatoid arthritis
4. Rheumatic fever
5. Liver diseases.

ESR decreases in the diseases such as:

1. Allergic conditions
2. Sickle cell anemia
3. Peptone shock
4. Polycythemia and
5. Severe leukocytosis.

Significance Of Determining ESR

• ESR is an easy, inexpensive and nonspecific test, which helps in diagnosis as well as prognosis.
• It is nonspecific because it cannot indicate the exact location or cause of disease.
• But, it helps to confirm the diagnosis. Prognosis means monitoring the course of disease and the response of the patient to therapy.
• Determination of ESR is especially helpful in assessing the progress of patients treated for certain chronic inflammatory disorders such as:

1. Pulmonary tuberculosis
2. Rheumatoid arthritis
3. Polymyalgia rheumatica (an inflammatory disease characterized by pain in the shoulder and hip)
4. Temporal arteritis (inflammatory disease of arteries of head).

Factors Affecting ESR

• The specific gravity of RBC: When the specific gravity of the RBC increases the cells become heavier and sedimentation is fast. So ESR increases
• Rouleaux formation: It increases the ESR. Globulin and fibrinogen accelerate rouleaux formation
• Increase in size of RBC: When the size of RBC increases (macrocyte), ESR also increases
• Viscosity of blood: Viscosity offers more resistance for settling of RBCs. So when the viscosity of blood increases, the ESR decreases.
• RBC Count: When RBC count increases, the viscosity of blood is increased. Increased viscosity offers resistance to settling down of RBCs. So ESR decreases. And when the RBC count decreases, ESR increases.