2. ERYTHROCYTE SEDIMENTATION RATE (ESR)
• The erythrocyte sedimentation rate (ESR) is a
nnoonnssppeecciiffiicc ssccrreeeenniinngg tteesstt indicative of
inflammation
• There are two methods of determining ESR:
Westergren and Wintrobe
• Studies have shown that the Wintrobe method
was found to be misleading in some important
cases
• As a result, the Westergren method is most widely
used
3. ERYTHROCYTE SEDIMENTATION RATE (ESR)
• Anticoagulated blood is drawn up into a tube of standardized
dimensions and left in a vertical position for exactly one hour.
• After that period the point at which the red cells have separated and
settled from the plasma is recorded by reading from the scale on the
side of the tube.
• This test measures the distance that RBCs will fall in a vertical tube
over a given time period
• It is used as an initial screening tool and also as a follow-up test to
monitor therapy and progression or remission of disease.
• The ESR is directly proportional to red cell mass
• The ESR is reported in millimeters
4. ERYTHROCYTE SEDIMENTATION RATE (ESR)
• Although the test has been used since 1926 the phenomenon
of red cell sedimentation is still only partly understood.
• However three definite phases have been identified in the
process.
• During the first, or Lag Phase, the red cells form a
characteristic rouleaux pattern and sedimentation is
generally slow.
• The rate accelerates in the second period, the Decantation
Phase, and slows again in the final Packing Phase as red cell
aggregates pile up at the base of the tube
5. ERYTHROCYTE SEDIMENTATION RATE (ESR)
• The size of the rouleaux aggregates formed in the Lag Phase is the
critical factor affecting the final result of the ESR.
• The rouleaux itself appears to be influenced mainly by certain plasma
proteins including fibrinogen, IgM and alpha2-macroglobulin.
• From the above it can be seen that the sedimentation 'rate' of the red
cells is not linear.
• Further, the time taken for each of the three phases will differ
between patients.
• Therefore no attempt should be made to 'estimate' the result at 1
hour by doubling the value at 30 minutes or multiplying by three after
20 minutes
6. ERYTHROCYTE SEDIMENTATION RATE (ESR)
• Any condition that will increase rouleaux formation will
usually increase the settling of red cells.
• Specimens that are not properly anticoagulated will
also affect red cell settling.
EDTA is the recommended anticoagulant
9. PROCEDURE – WESTERGREN METHOD
• 1. Mix the EDTA tube on the rotator/mixer for a
minimum of 5 minutes.
If the sample has been refrigerated, allow 30 minutes
for the sample to come to room temperature before
proceeding.
Hold the filling reservoir and shake downwards with a
flick the wrist to force the saline to the bottom
Keep upright and remove cap
10. PROCEDURE – WESTERGREN METHOD
• 2. Add 1ml well mixed EDTA whole blood to the filling line of the
reservoir.
• 3. Replace Cap
• 4. Gently mix by inversion (minimum of 8 inversions)
• 5. Place on flat surface an make sure that all the blood return
back to the bottom of the reservoir
11. PROCEDURE – WESTERGREN METHOD
• 6. Hold the reservoir firmly in one hand and the Dispette tube in the
other hand with the 180 mark towards the bottom
Penetrate the cap membrane and stop
• 7. With gentle movements, continue to penetrate the reservoir
towards the bottom
Making sure that the blood is rising to the top until it reaches the
grommet at the zero mark
When the Dispette is fully inserted, any extra blood will be
accommodated by the plugged overflow chamber
12. PROCEDURE – WESTERGREN METHOD
• 8. Place the fully assembled Dispette
apparatus in a level stand at 90
degrees to the stand
Read and record the results in
millimeters at exactly one hour after
settling upright (distance which the
cells have settled)
13. PROCEDURE – WINTROBE METHOD
• 1. Add well mixed EDTA blood to the zero mark of the Wintrobe
tube, using a pipette
Avoid air bubbles
• 2. Place in vertical position in a rack and let sit for 60 minutes
• 3. Read and record results in millimeter (distance which the cells
have settled)
15. LIMITATIONS
• 1. Tubes not filled properly will yield erroneous results.
• 2. Refrigerated specimens must come to room temperature for 30
minutes prior to testing.
• 3. The ESR rack must be on a level surface and free of vibration.
Vibration can cause a falsely increased ESR.
• 4. Cold agglutinins can cause a falsely elevated ESR.
An ESR can be performed at 37 degrees C (incubator) for 60 minutes with
no ill effects.
• 5. Red cell shape and size: Specimens containing sickle cells,
acanthocytes, or spherocytes will settle slowly and give a decreased ESR
• 6. Increased rouleaux formation, excessive globulin, or increased
fibrinogen will increase the ESR.
16. LIMITATIONS
• 7. Specimen must be free of clots and/or fibrin.
• 8. A tilted ESR tube gives erroneous results.
• 9. Hemolyzed samples are not acceptable.
• 10. Specimens older than 24 hours are not acceptable.
• 11. Do not pick up the stand to read results as this will affect other
tests in progress.
Bring the eye to the level of the top of the red cells to read
accurately from the scale
• 12. Results must be read at exactly one hour, otherwise the cells
with continue to sediment resulting in higher results