The term ESR indicates the erythrocyte sedimentation rate (sedimentation rate of red blood cells, called erythrocytes, present in the blood). The test measures the time it takes for red blood cells to separate from the liquid part of the blood (plasma) and settle to the bottom of a tube. The result is calculated in millimeters of plasma present in the upper part of the tube after one hour.
The exam is useful for identifying the presence of inflammation and, although it is not very specific and not very sensitive, since it does not give precise information on the disease that caused the inflammation, it is widely used, especially because it is cheap and easy to perform. It is generally prescribed together with other tests such as the examination of C-reactive protein (PCR) or mucoproteins.
ESR may be recommended by the doctor in several cases:
- when you suspect the presence of inflammation or infection: for example, if an individual tends to get sick often, due to a lowering of the immune defenses, and has disorders (symptoms) associated with inflammation such as pharyngitis, otitis, bronchitis, or fever that recurs over time (recurrent )
- when a person experiences ailments (symptoms) that may be associated with diseases such as transient arthritis, rheumatic polymyalgia, systemic vasculitis or rheumatoid arthritis
The ESR is a very simple test, has no contraindications and is carried out by simply taking a small amount of blood (sample) from a vein in the arm.
It is not necessary to be fasting even if, often, in analysis laboratories it is still required. After the blood collection, you can immediately return to normal activities.
Some drugs can affect the test result by increasing or decreasing the ESR; for this reason, if you are undergoing drug treatment, it is important that your doctor is aware of it.
Women usually have a higher ESR than men. Pregnancy, as well as menstruation can cause an increase in ESR.
The ESR is measured in millimeters per hour and the normal values (reference values) in the analysis results are differentiated by sex and age:
- men between 20 and 49 years old: the ESR on average is equal to 5 mm / h but the range in which it is considered normal is between 0 and 13 mm / h
- men between 50 and 69 yearsi: the ESR on average is equal to 7 mm / h but the range in which it is considered normal is between 0 and 19 mm / h
- women between 20 and 49 years old: the ESR on average is equal to 9 mm / h but the range in which it is considered normal is between 0 and 21 mm / h
- women between 50 and 69 years old: the ESR on average is equal to 12 mm / h but the range in which it is considered normal is between 0- and 28 mm / h
The test result may be affected by factors not dependent on a disease or, in any case, not directly related to inflammation.
You can have a higher than normal ESR in the presence of:
- old age
- female sex
- tissue necrosis (following trauma)
- inflammations already overcome
- red blood cells of above average size such as, for example, in macrocytosis (elevated MCV)
- lymphoproliferative diseases, which include infectious diseases, such as mononucleosis, and cancer diseases, such as leukemias and lymphomas
You can have a lower than normal ESR in the presence of:
- young age
- male sex
- increase in the number of red blood cells (polyglobulia)
- red blood cells below average size, eg. in microcytosis (low MCV)
Among the pathologies that cause an increase in the ESR value we remember:
- endocarditis, inflammation of the inner lining of the heart
- gout, a type of acute arthritis caused by uric acid crystals usually deposited in the joints
- thyroid disease
- kidney disease
- rheumatic fever
- rheumatoid arthritis
- acute allergy
- systemic lupus erythematosus
- myocardial infarction
- pulmonary infarction
- acute meningitis
- multiple myeloma
- necrotizing vasculitis
- polymyalgia rheumatica
- giant cell arteritis