Definition: The method for measuring the ESR recommended by the international council for standardization in hematology(ICSH) and also by various national authorities is based on that of Westergren, who developed the test in 1921 for studying patients with pulmonary tuberculosis. ESR is the measurement of the sedimentation of red cell  in diluted blood after standing for 1 h in an open-ended glass tube of 30 cm length mounted vertically on a stand.

Principle: If an anticoagulated blood is placed in narrow tube, the red cell settle down leaving the clear plasma above them. In ESR, the distance that the red cell have fallen within a distance interval of time is measured.

The rate of erythrocyte sedimentation depends upon the interaction between opposing physical forces. Settling occurs because the density of red cell is greater than the density of the medium. The fall of red cells causes an upward displacement of the medium, thus producing an upward current and retarding force. Blood drawn from the normal person has an equal downward and upward force, hence a little sedimentation occurs. When the number of red cell is less, there is less retardation of sedimentation by the RBCs themselves and tend to settle faster, this is anemia.

Stages of sedimentation

1. Formation of rouleaux phase ( 10 minutes): is the linking of RBCs into chain resembling stacks of coins.

2. Sinking of rouleaux phase  (40 minutes):Rapid and constant sedimentation. 

3. Packing of rouleaux (10 minutes):Sedimentation slow and cell start to pack at the bottom of the tube.

Estimation of Erythrocyte sedimentation rate

There are two methods for measuring ESR:

1. Wintrobe’s Method:

  • In the method, a smaller diameter 100mm tube containing EDTA anticoagulant is used to collect venous blood. 
  • Once collected, the blood is held in a vertical position for 1 hour to permit RBCcollection at the bottom.
  • The ESR is measured in the same manner as done for the  Westergren method. 
  • Due to the limited length of the wintrobe’stube (100mm),ESR measurement are subject to inaccuracy and abnormal readings. 
  • Essentially, this method is convenient for demonstration purpose only.

Reference value:  0-10mm/1st hour in male

                                                 0- 20 mm/ 1sthour in female

2.  Westergren’s method: 

In which the Westergren glass pipette of 300 mm length is used and blood is diluted with 3.2% trisodium citrate in a ratio of 1:4 ( 1 part citrate and 4 part blood ).


  • Mix the whole blood for a least 2 minuteson a rotator. Check the tube for clots using tow application sticks.
  • The recommended tube is a straight glass tube of 300 mm length and 2.55 mminternal diameter.
  • Place the tube in an exactly vertical position in the rack time for 60 minutes.
  • Read the height of clear plasma above the upper limit of the column of sedimentationcell to the nearest mm mark.
  • Reported as mm in 1st hour.

Reference value :   Males : 0-15 mm/1sthour 

                                       Females : 0-20mm/1st hour

Conditions associated with increased ESR 

  • Tuberculosis, rheumatoid  arthritis and osteomyelitis.
  • Collagen vascular disease like SLE 
  • Stroke , MI
  • Multiple myeloma
  • Diagnostics role in giant cell  temporal arteritis

Conditions associated with decreased ESR

  • Polycythemia vera
  • Hereditary spherocytosis
  • Sickle cell disease 
  • Hypo fibrinogenemia•€Congestive heart failure