In this article we will discuss about:- 1. Mechanism of ESR 2. Determination of ESR 3. Factors 4. Significance.
Mechanism of ESR (Erythrocyte Sedimentation Rate):
ESR can be observed to take place in three stages:
1. A preliminary in which taken, at least few minutes to form roleaux (aggregation of cell occur).
2. Then the period in which sinking of the Roleaux taken place (on rapid fall).
3. Finally a phase during which the ESR shows and Roleaux packed at the bottom of tube.
Determination of ESR:
I. Westergren’s Method:
The westergren pipette is straight glass tube 30cm (300mm) in length and 2.5mm in diameter. It is calibrated in mm from 0.200mm. Venous blood is diluted with 3.8gm/litre trisodium citrate in which proportion of 1 part of citrate and four part of blood. The test should be carried out within two hour of collecting the blood.
The sample is well mixed and blood is drawn up to the westergren pipette to the 200mm mark. The height of clear plasma above the up to limit of locums of sedimenting red cell in then read to the nearest used the westergren stand. It is conventional to setup ESR at room temperature. Sedimentation is normally accelerated as the temperature rise.
Normal Value:
Male – 0-9 mm in one hour
Female – 0-20 mm in one hour
II. Wintrobe Method:
Reagents and Apparatus:
I. Wintrob’s Tube:
This is a thick walled tube 110 mm long having an internal diameter of 2.5mm. The tube is graduated from 0-100 mm.
II. Anticoagulant Blood:
Either balanced oxalates or EDTA can be used.
III. Long stemmed pastuer pipette (or long metallic needle attached to a syringe)
IV. Sedimentation rack (wintrobe’s method)
Method:
I. The venous anti-coagulated blood is mixed well and wintrobe tube is filled to the ‘o’ mark using a long needle or pasture pipette.
II. The distance, the meniscus has fallen in one hour is recorded as ESR.
Normal Value:
Male – 0-7mm for 1 hour
Female – 0-10mm in 1 hour
Factors Influencing ESR:
The ESR is influenced by number of interacting factors:
1. Basically it depends upon the difference in specific gravity in the red cells and plasma.
2. Actual rate of fall is influenced greatly by the extent to which the red cells form rouleaux as large dumps of cell adhering to each other to side sediment more rapidly than single cells.
3. Ratio between red cells and plasma.
4. Protein concentration in plasma a fibrinogen and globulins are more responsible for the formation.
5. Fat contents of blood.
6. Temperature of blood.
7. Diameter and length of the tube.
8. Angle at which the tube is kept.
9. Anticoagulant is used and dilution of blood with it.
10. Age of blood also.
The difibrinated blood sediments normally extremely slow.
Significance of ESR:
1. It gives the knowledge of plasma protein roughly.
2. Use of some chronic disorder i.e. tuberculosis as an index of progress of diseases and it is usefulness in the routine examination of protein.
3. It is the significance test for degenerative and neoplastic disease associated with change in plasma proteins.
4. Anemia increases the ESR.
5. It depends on age and sex also.
The test is nonspecific the ESR being increased in all conditions in which tissue distraction and inflammation is present. This markers are useful guide in assessing the progress woeful in following the condition of schematics and tuberculosis patient.