Inflammation is a process that can occur in the body as a result of infection or injury. When looking for markers of inflammation in the blood, one test that comes to mind is the erythrocyte sedimentation rate. Also called ESR, this test is a simple blood test that provides valuable information regarding any underlying disease process. In this article, we shall take a brief look at what ESR is and what its clinical implications are.
Obtaining a Blood Sample
As is the case with any blood test, a small amount of blood is withdrawn from a large vein and collected in a special tube. Once the blood is withdrawn, it is held in a clinical laboratory and stable position to allow the red blood cells to settle and the bottom of the sample. The rate at which the blood cells settle is what the erythrocyte sedimentation rate is.
The erythrocyte sedimentation rate may be performed as a part of an investigation panel for a number of different clinical conditions. In particular, it is very effective in aiding a diagnosis of clinical conditions such as rheumatoid arthritis, temporal arthritis and other inflammatory conditions. It also helps diagnose infection such as tuberculosis. Autoimmune conditions such as systemic lupus erythematosus can also be diagnosed with the help of ESR.
Normal value of ESR is less than 20 mm/hr in adults. This means that the blood cells settle at a rate of 20 mm in one hour.
An elevated ESR can be seen in conditions such as cancer, tuberculosis and anemia. ESR may also be elevated in pregnant women. As has been discussed previously, ESR can also be elevated in arthritic conditions such as rheumatoid arthritis and autoimmune conditions such as systemic lupus erythematosus and giant cell arthritis. Patients with thyroid disease can also have high values of ESR.
Cons of ESR Test
The problem with the ESR the test is that it is not specific. Even patients who have chest infections can have elevated levels of ESR. As such, it is not a particularly diagnostic test but is useful as an addendum to a battery of other tests that may be performed for a clinical condition. Levels of ESR may be mildly elevated in congestive cardiac failure and sickle cell anemia.
Not every patient who gets admitted to hospital requires an erythrocyte sedimentation rate test. After a detailed clinical history is taken and an examination is performed, the actual requirement of an ESR will be ascertained. In conditions such as temporal arthritis and autoimmune conditions, an ESR is extremely useful. In conditions such as simple infections and heart failure, and ESR is not useful and may not be performed.
An erythrocyte sedimentation rate test is a useful test in aiding clinical diagnosis of the number of different conditions. It is simple to perform and can be very valuable.