The normal rate of ESR in the blood is age-dependent:
Men over 50 years old: 3 - 20 mm/h
Men under 50 years old: 2 - 15 mm/h
Women over 50 years old: 3 - 30 mm/h
Women under 50 years old: 2 - 20 mm/h
Children up to 15 days old: 2 - 11 mm/h
Newborns: 0 - 2 mm/h
Each laboratory must establish its own normal rates for ESR in a blood test. These ranges depend on the makeup of the local population, the technologies used and the accuracy of the measurement. There may be also slight differences in the normal rates according to age, gender, race or ethnic origin, geographic region, diet, type of sample and other relevant status.
Your doctor will study the results along with your medical record, screenings, physical condition, symptoms and any other relevant information about your situation.
There are different methods to measure the ESR and depending on the method used, the normal range may differ. The most used one is the Westergren's Method where a blood sample is mixed with a 3.8% trisodium citrate solution. They are also used the Wintrobe's method, microsedimentation (Landau) method or Zeta Sedimentation Rate (ZSR).
In pregnant women, normal ranges are significantly higher (44 - 114 mm/h). In this case, the normal ranges expressed by the laboratory must be observed.
The ESR (Erythrocyte Sedimentation Rate) is the rate at which erythrocytes sediment on their own weight when anticoagulated blood is held in a vertical column. It is usually measured in a typical routine blood test.
The test is done by mixing a sample of blood with sodium citrate as anticoagulant (or a similar one) in a vertical tube test for a certain time (usually an hour). By that time, the RBCs (Red Blood Cells) present in the blood precipitate due to their higher density than the plasma. ESR is expressed as the fall of RBCs in mm at the end of the first hour (starting point—when the tube or pipette was filled with blood).
Sedimentation occurs because the erythrocytes clump or aggregate together in a column-like manner (rouleaux formation).The normal time to perform this test is one hour, but it can be done in more time. The results of the test are expressed as millimeters per hour (mm/hr.)
Inflammation creates proteins that make red blood cells fall more quickly and increases ESR.
ESR is an indirect measure of the level of acute phase proteins in the blood.
This test is based on the fact that inflammatory and necrotic processes cause an alteration in blood proteins, resulting in aggregation of RBCs, which makes them heavier and more likely to fall rapidly when placed in a special vertical test tube. The faster the settling of cells, the higher the ESR.
An accelerated ESR is favored by elevated levels of fibrinogen, and to a lesser extent, of globulins (alpha and beta globulins are more effective than gamma globulin), immunoglobulins and albumin.
The ESR is neither sensitive nor specific as a general screening test. It should be used in combination with other tests to get a proper diagnosis.
The main objective of the ESR (erythrocyte sedimentation rate) test is:
The sedimentation rate is not diagnostic of any particular disease, but rather is an indication that a disease process (infection or inflammation) is ongoing and must be investigated. The ESR should not be used to screen asymptomatic patients for disease.
It is also useful in monitoring the progression of inflammatory diseases; if the patient is being treated with steroids, the ESR will decrease with clinical improvement.
A marked increase in the ESR rate during pregnancy (first months) is a normal occurrence because there is an increase in the globulin and fibrinogen levels during pregnancy.
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The following rates are considered to be normal values:
IMPORTANT: These rates are expressed in mm/h (millimeter/hour). They are an example of a healthy man of about 40 years old with no known disease and not taking any medication. The rates can be different depending on the laboratory or on your personal circumstances.
|2 mm/h||3 mm/h||4 mm/h||5 mm/h||6 mm/h||7 mm/h||8 mm/h||9 mm/h|
|10 mm/h||11 mm/h||12 mm/h||13 mm/h||14 mm/h||15 mm/h|