Erythrocyte Sedimentation Rate (ESR): Procedure

DEFINITION OF Erythrocyte Sedimentation Rate:

ESR is a measure of settling down of RBCs in an anticoagulated specimen of whole blood during a specified period of time.

APPARATUS

• WST = Westergren’s tube
• WTB = Wintrobe’s tube

Westergren’s tube (pipette) with stand, Wintrobe’s tube with stand, long nozzled capillary pipette (Pasture pipette), anticoagulants 3.8% sodium citrate solution (liquid form of anticoagulant), mixture of double oxalate, EDTA (powdered form of anticoagulant), petri dish containing 1.6 ml blood and 0.4 ml of 38% tri-sodium citrate, 2 ml disposable plastic syringe with needle and spirit swab.

Westergren’s Tube with Stand:

• It is a thick walled glass tube of length 30 cm, open at both the ends with internal bore 2.5 mm.
• Tube is graduated along the lower 2/3 portion, 0-200 mm from up to down.
•  Westergren’s stand: Tall stand for holding the Westengren’s tube vertically with rubber pad at the bottom and screw at the upper end .

Wintrobe’s Tube with Stand:

• It is a thick walled glass tube of length 11 cm, closed at one end with internal bore of 2.5 mm.
• Lower 10 cm of the tube is graduated from 0-100 mm from top to bottom and  bottom to upper end.
• Markings from 0-100 mm from upto down are used for reading ESR and markings from bottom to upward used for reading PCV (hematocrit).
• Wintrobe’s stand: It is a small stand as compared to Westergren’s stand. lt is used to keep the Wintrobe’s tube vertically.
• The left sided series are used for ESR with O at the top. It is expressed as ESR (Wintrobe, 1st hour) = …… mm.

ERYTHROCYTE SEDIMENTATION RATE (ESR):

The Erythrocyte sedimentation rate  is a measure of settling of the red blood cells in an anti-coagulated whole blood sample which is allowed to stand in a narrow vertical tube during a specified period of time.

Westergren’s Method:

Westergren’s tube is used to measure ESR in this method:

PROCEDURE:

• perform the test at the temperature of 22-27°F.
• Press the tube after placing it’s lower end on rubber pad in the stand and fix the tube vertically in the stand with the help of screw.
•  Take 0.5 ml of 3.8% sodium citrate solution in a clean and dry glass vial. 2. Withdraw 2 ml of blood from anticubital vein in a all aseptic conditions. Remove the needle of the syringe and transfer the blood in vial containing sodium citrate solution. immediately mix the content.
• Suck citrated blood in Westergren’s tube up to mark ‘0’ and immediately close its upper opening with the help of index finger or thumb.
• Note the time and take the reading for ESR at the end of one hour of clean plasma column.
• Distance from bottom of plasma meniscus (at ‘0’ mark) to the top of RBC column is measured. The buffy coat is not included in the reading. The buffy coat can be used to prepare a blood film for WBCs and platelets.

 

• Wintrobe’s Method:

wintrobe’s tube is used to determine ESR by this method.

PROCEDURE:

• Mix the blood with anticoagulant gently.
• Draw 2 ml of blood from anticubital vein in all aseptic conditions and remove the needle of the syringe and eject the blood in glass vial.
• Take powder mixture of double oxalate (ammonium and potassium in ratio of 3:2) in a clean and dry glass vial. ‘
• Fill this blood in pasture pipette and introduce the capillary tube of pipette up to the bottom of Wintrobe’s tube.
•  Now apply the pressure on rubber teat and slowly take the pipette nozzle out so that tube will be filled up with the blood up to mark zero.
• Note down the time and put the tube in the stand for one hour. Take the reading of clean plasma column at the end of one hour.

Normal Value:

1. Man: O -9 mm at the end of 1st hour.
2. Woman: 0 20 mm at the end of 1st hour.

Precautions:

• The table on which the test is performed should be free of vibration.
• The rack should be leveled because slight tilt of the rack can give high ESR values.
• Over anti coagulation causes lower ESR values. .
• Test should be done within 4 hours, otherwise RBCs will become spherical at room temperature.
• There should be no air bubble in ESR tube.
•  ESR tube should be clean and dry.
• Blood sample must be collected in fasting state.
• Single oxalate should not be used as anticoagulant in Wintrobe’s method.
• Do not disturb the tube once kept in the stand for ESR.
• If the anticoagulant used is ethylene diamine tetra-acetic acid (EDTA) and the sample is refrigerated then it can be tested for ESR upto 12 hours after collection of the sample. The temperature of the blood sample should be brought at room temperature before doing the test.
• High temperature increases ESR value while low temperature can give decreased ESR value.

Variation in Erythrocyte Sedimentation Rate:

Increase in ESR is seen in physiological and pathological conditions:

(a) Physiological

•  Pregnancy
• Menstruation
•  Increased temperature
• Higher in femaleVariation in ESR

Increase in ESR is seen in physiological and pathological conditions:

(a) Physiological

•  Pregnancy
• Menstruation
•  Increased temperature
•  Higher in female