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Erythrocyte Sedimentation Rate (ESR) 10

الكلية كلية طب الاسنان     القسم  العلوم الاساسية     المرحلة 2
أستاذ المادة وسن نجم عبد السادة الربيعي       22/02/2019 23:26:08
Erythrocyte Sedimentation Rate (ESR)

ESR: Is the distance (in millimeter) that erythrocytes fall per unit of time (usually 1 hour) .If anticoagulant blood is allowed to stand vertically in a tube undisturbed ,the RBCs will gradually fall to the upper portion .The distance that the cells fall in 1 hour can be measured and is called the sedimentation rate .This sedimentation occurs in three stages :
1.Formation of rouleaux; rouleaux is formed with minimal sedimentation. This phase lasts about 10 minutes .
2.Period of fast settling ;at this stage the settling rate is constant and lasts about 40 minutes.
3.The remaning amount of time is a period of packing of the rouleaux at the bottom of the tube .
Rouleaux: The stacking up of red blood cells, caused by extra or abnormal proteins in the blood that decrease the normal distance red cells maintain between each other (Fig.1).

Figure (1) : Rouleaux phenomenon is seen on a peripheral blood smear.
Factors affecting ESR
1.Size of RBCs: In vitamin B12 deficiency RBCs are large in size Macrocytes, and the sedimentation rate increased, while in iron deficiency the RBCs are small in size Microcytes and the sedimentation rate decreased.
2.Number of RBCs: In anemia; ESR increased, while in polycythemia; ESR decreased.
3.Plasma proteins concentration: The more plasma protein present, the more rapidly rouleaux phenomena will occur and the more elevated the sedimentation rate will be.
4.Hemoglobin content .
5.Blood viscosity .
6.Rouleaux formation .

The Principle
The blood is diluted with anticoagulant diluting fluid; in the westergren tubes set up vertically for one hour and then read the highest of the clear plasma above the upper limit of the column of sediment red cells in millimeter.

Objective
To estimate the ESR of whole blood sample.

Apparatus and Reagents
Westergren Method :
1.Westergren tube :It is 300 mm in length are marked from 0 (top) to 200 (bottom) ;open at both ends ,diameter of 2.5 mm.
2.Westergren rack :With adjustable leveling screws are available for holding the sedimentation tubes in vertical position (Fig.2) .
3. (3.8%) Trisodium citrate solution as anticoagulant diluting fluid .
4.Venous blood sample .
5.Test tubes .
6.Pipette 0.5 ml.

Procedure
1.Place 0.5 ml of 3.8% Trisodium citrate in test tube.
2.Add 2 ml of blood sample to the test tube .(1 part of 3.8% Trisodium citrate to 4 parts of blood ) .
3.Mix the contents of test tube gently.
4.Fill the westergren tube to 0 mark .
5.Set up the westergren tube right in a stand with a spring clip on top and rubber at bottom .
6.Read the highest of the clear plasma above the upper limit of the column of sediment red cells in mm/hr .

Clinical Applications
ESR Increased in:
1.Chronic condition such as Rheumatiod arthritis and Tuberculosis .
2.A cancer of a certain type of white cells Multiple myeloma ,where the plasma proteins are abnormal.
3.Acute infections .
4.Anemia.
5.Kidney disease .
6.Autoimmune and inflammatory diseases .
7.Pregnancy .

ESR Decreased in:
Any disease that changes the shape and size of red blood cells decrease the ESR; also the diseases that cause the body to make less protein or extra RBCs decrease the ESR, such as :
1.Sickle cell disease .
2.Polycythemia .
3.Congestive heart failure .

Normal Value
Children : 0-10 mm/hr
Women : 0-20 mm/hr
Men : 0-15 mm/hr
Increase by 5 to 10 mm/hr in persons older than 50 years of age .

Figure (2):Westergren apparatus consist of (A) Westergren tubes (B)
Westergren rack.



Precautions
1.As blood is taken by vein puncture prolonged venous congestion must be avoided .
2.They set up with in three hours of blood collection .
3.Tests must not be Performed in direct sunlight .
4.They performed in 18-22 C° .
5.Blood containing the slightest trace of clot must be discarded .
6.Hemolysed blood must not be used .






















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