Aim: To estimate the erythrocyte sedimentation rate of my own blood sample.
Principle:
When a normal blood column is kept vertically for some time the RBCs will settle down to the bottom. E.S.R is the state of measure of the suspension stability of RBC. If a vertical column of citrated blood is kept, the red cell begins to settle until they form a packed volume at bottom of pipette. There are three stages of sedimentation.
- Stage of aggregation in the first 10 minutes.
- Stage of rapid sedimentation taking up to 40 minutes.
- Stage of steady packing of cells.
The length of the plasma column at the top of blood column at the end of first hour is measured in mm.
Methods of estimation of E.S.R :
- Westergren's method : Westergren's pipette is a 30cm long glass tube having a diameter of 2.5mm. It is graduated from above downwards from 0 to200. The anti coagualnt used is 3.8% sodium citrate or EDTA is also used.
- Wintrobe's method : In this method haematocrit tube is used. It is a cylindrical tubr open at one end. The total length is 11cm. The tube is uniform and has an internal diameter of 2.5mm. It is graduated from 0 to 10. The anti coagulant used is sodium citrate, EDTA or double oxalate.
Procedure:
Westergren's method: Blood is collected and mixed with anti coagulant in the ratio 1:4. The temperature should be 25-28 degree celcius. Blood is drawn up to the mark 0. The tube is kept exactly vertical for 1 hour in a stand. The height of plasma column after one hour is noted.
Result: E.S.R of the given sample of blood by Westergren's method is ______ mm/after 1st hour.
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