ESR
Formal name: Erythrocyte Sedimentation Rate
How is it used?
The erythrocyte sedimentation rate is a relatively simple, inexpensive, non-specific test that has been used to help detect inflammation associated with conditions such as infections, cancers and autoimmune diseases.
ESR is said to be non-specific test because an elevated result often indicates the presence of inflammation. For this reason, the ESR is typically used in conjunctions with other tests, such as C-reactive protein.
ESR is used to help diagnose certain specific inflammatory diseases, temporal arteritis, systemic vasculitis and polymyalgia rheumatica. A significantly elevated ESR is one of the main test results used to support the diagnosis.
This test may also be used to monitor disease activity and response to therapy in both of the above diseases some others for example Systemic Lupus Erythematosus (SLE).
When is it ordered?
An ESR may be ordered when a condition or disease is suspected of causing inflammation in the body. There are numerous inflammation and pain in the joints or when digestive symptoms that suggest polymyalgia rheumatica, systemic vasculitis, or temporal arteritis, such as headaches, neck or shoulder pain, pelvic pain, anemia, poor appetite, unexplained weight loss, and joint stiffness
What does the test result mean?
The result of an ESR is reported as the millimeter of clear fluid (plasma) that are present at the top portion of the tube after one hour (mm/hr).
Since ESR is a non-specific marker of inflammation and is affected by other factors, the results must be used along with other clinical findings, the individual’s health history, and results from other laboratory tests. If the ESR and clinical findings match, the health practitioner may be able to confirm or rule out a suspected diagnosis.
A single elevated ESR, without any symptoms of a specific disease, will usually not give enough information to make a medical decision. Furthermore, a normal result does not rule out inflammation or disease.
Moderately elevated ESR occurs with inflammation but also with anemia, infection, pregnancy, and with aging.
A very high ESR usually has an obvious cause, such as a severe infection, marked by an increase in globulins, polymyalgia rheumatica or temporal arteritis. A health practitioner will typically use other follow-up tests, such as blood cultures, depending on the person’s symptoms.
When monitoring a condition over time, rising ESRs may indicate increasing inflammation or a poor response to a therapy; normal or decreasing ESRs may indicate an appropriate response to treatment.
Is there anything else I should know?
A low ESR can be seen with conditions that inhibit the normal sedimentation of red blood cells, such as a high red blood cell count, significantly high white blood cell count (leukocytosis), and some protein abnormalities. Some changes in red cell shape (such as sickle cells in sickle cell anemia) also lower the ESR.
ESR and C-reactive protein(CRP) are both markers of inflammation. Generally, ESR does not change as rapidly as does CRP, either at the start of inflammation or as it resolves. CRP is not affected by as many other factors as is ESR, making it a better marker of inflammation. However, because ESR is an easily performed test, many health practitioners still use ESR as an initial test when they think a patient has inflammation.
Women tend to have a higher ESR, and menstruation and pregnancy can cause temporary elevations.
In a pediatric setting, the ESR test is used for the diagnosis and monitoring of children with rheumatoid arthritis or Kawasaki disease.
Drugs such as dextran, methyldopa, oral contraceptives, penicillamine procainamide, theophylline, and vitamin A can increase ESR, while aspirin, cortisone, and quinine may decrease it.