Erythrocyte Sedimentation Rate
(ESR)
General physiology
Practical (3)
BMS 115
Erythrocyte Sedimentation Rate
Erythrocyte red blood cells (RBCs)
Sedimentation settle down of RBCs
Rate number of RBCs settle down in given time
Principle and definition of ESR
• If the blood is left in a vertical, undisturbed test tube and kept
anticoagulated, the blood separates , the denser components sink
to the bottom of the tube and fluid remains at the top, finally,
RBCs will be sediment by effect of gravity.
• So ESR is the distance in millimeters sedimented by
RBCs in vertical blood column after one &two hours
• ESR reported as mm/hr.
Erythrocyte Sedimentation Rate
Principle
Normally, RBCs membrane has -ve charges, therefore, in the circulation they repel each
other (no sedimentation inside the circulatory system).
But, when the blood is placed in a vertical, undisturbed test tube and kept anticoagulated
for 2 hrs., the RBCs will sedimented.
Sedimentation occurs due to the increased release of plasma proteins (such as fibrinogen
& globulins, they cause a reduction in –ve charge of RBCs membrane), which neutralize
the erythrocyte membrane charge resulting in aggregation of RBCs in a column (rouleaux).
The higher fibrinogen and globulins, the faster rouleaux formation, the higher the ESR.
Rouleaux formation
Definition?
Plasma (fibrinogen,
proteins Globulins)
+ +
+ +
+ + Repulsion
+ +
force
+ +
Rouleaux
formation
Stages of ESR sedimentation
The sedimentation rate of RBCs takes place in three stages:
1. First Stage: rouleaux formation
2. Second Stage: cells settle rapidly.
3. Third Stage: packing occurs, and RBCs accumulate in the bottom of the tube.
Tools
1. Westergren erythrocyte sedimentation tube.
Open on both ends.
30 cm in length .
Marking on the tube is from 0 to 200 mm.
2. Holding rack is used.
3. Vacuum tube which contain 3.8% sodium
citrate as anticoagulant factor.
Steps
1- Mix 2 ml blood with 0.5 ml anticoagulant .
( Na citrate 3.8 %).
2- Put it in Westergren’s tube.
3- Vertical and Undisturbed for 1 & 2 hrs.
0
Normal value : 10
20
30
40
50
60
Clinical significance
Physiological increase of ESR:
• Menstruation (due to increase of fibrinogen).
• Pregnancy (due to increase of globulins).
Pathological increase of ESR:
• Any condition or disease that increases the protein level
(or tissue destruction ), increases the sedimentation rate.
• Infections, rheumatic fever, cancers or autoimmune
diseases.
Decrease of ESR: hypofibrinogenemia or Afibrinogenemia.
Notes
• ESR test Not Diagnostic but prognostic.
Diagnosis?
