Experiment 7
Suaad Mohammad (M.Sc.)
Erythrocyte Sedimentation Rate (ESR)
If an anticoagulant is added to the blood and the specimen allowed
to stand in a tube, red cells slowly sediment to the bottom of the tube
leaving clear plasma as the supernatant.
The rate of sedimentation estimated under standard conditions is
known as the erythrocyte sedimentation rate (ESR).
The number of millimeters the red cells fall during the end of 1 hour
constitutes the ESR result.
The rate is usually increased in inflammatory infections, toxemia, cell or
tissue destruction, severe anemia, active tuberculosis, syphilis, acute
coronary thrombosis, rheumatoid arthritis, and malignant processes.
Sickle cell anemia, polycythemia, hypofibrinogenemia, and certain drugs
usually decrease the rate.
Sedimentation takes place in three stages:
1- Formation of rouleaux, 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- Final stage, the remaining amount of time is a period of packing of
the rouleaux at the bottom of the tube.
Procedure
Westergren tube:
(open at both
Length – 300 mm
ends)
Diameter 2.5mm
a- The lower 200 mm are marked from 0 (top) to 200 (bottom).
b- Anticoagulant used is 3.8 % trisodium citrate solution. 1 part of
anticoagulant is added to 4 part of blood ( 0.5 ml of anticoagulant is
used for 2 ml blood).
c- The mixture is drawn in to a westergren tube up to the zero mark
and the tube set upright in a stand with a spring clip on top and
rubber at bottom.
d- The level of the top of the red cell column is read at the end of 1
hour.
Male : 3 – 5 mm/hour
Female: 4 – 7 mm/hour
The number of millimeters the red cells fall during this tie period
constitutes the ESR result
1) The erythrocyte sedimentation rate is a nonspecific test that suggests
the possibility of a disease process and tissue damage in the body. It is not
diagnostic but is extremely useful in following the course of some diseases.
(2) The rate is usually increased in inflammatory infections, toxemia, cell or
tissue destruction, severe anemia, active tuberculosis, syphilis, acute
coronary thrombosis, rheumatoid arthritis, and malignant processes.
(3) Sickle cell anemia, polycythemia, hypofibrinogenemia, and certain drugs
usually decrease the rate.
Normal valuesMales: 1-4 mm/lst Hr.
Females : 3-10 mm/lst Hr.
ESR is the rate at which erythrocytes sediment in anticoagulated blood
kept undisturbed. RBC5 settle down due to their greater specific gravity
than that of plasma.
Factors influencing ESR :
1. Rou leaux formation is a very important factor on which ESR depends.
When the degree of rouleaux formation is more (the ratio of surface area
to mass of RBC is less) ESR is more Rouleaux
formation is influenced by different factors like:a. Shape of RBC - Biconcave disc shape favour rouleaux formation
b. Plasma proteins Albumin reduces rouleaux formation, Fibrinogen
favours rouleaux formation
c. Products of tissue destruction and inflammation favour rouleaux
formation.
The above plasma factors affect rouleaux formation by changing the
electrical charges on the red cells.
2. Size of RBC when more, faster sedimentationConditions in which ESR
value is increased
1. Physiological conditions like menstruation, pregnancy
2. Pathological conditions a.Rheumatic fever, rheumatoid arthritis,
tuberculosis, malignancy, acute inflammatory diseases. Severe tissue
breakdown occurs in the aboveconditions. b. Anaemia Decrease in ESR
value: 1. Physiologically in newborns 2. Polycythaemia 3. Spherocytosis 4.
Afibrinogenemia Clinical Significance of ESR In the past, much clinical
importance was given to ESR as a diagnostic and prognostic tool in the
assessment of several pathological conditions like rheumatic fever,
tuberculosis etc. Abnormal ESR value alone is not diagnostic of any disease
condition, but with other evidences, it helps in diagnosis. ESR has a more
prognostic significance ie it helps in assessing the course taken by a disease
in response to treatment eg. tuberculosis, collagen diseases. Precautions 1.
There should not be any air bubble in the blood column 2. The top level of
bloodcolumn should exactly correspond to zero level. 3. The pipette should
be mounted vertically. Other methods Wintrobes’s method: Here the
Wintrobe’s heamatocrit tube is used as in the other method, for
determining ESR. Questions: 1. Draw and label Westergren’s pipette. 2.
Write about other methods for the measurement of ESR. 3. What are the
quantities of Blood and anticoagulant taken for ESR estimation in Clinics?
Result: