An erythrocyte sedimentation rate (ESR) test is used for measuring inflammation in your body. Healthcare providers use this test, along with other diagnostic tests, to identify inflammatory conditions or keep track of existing conditions such as arthritis.
If there are concerns regarding elevated inflammation levels, a healthcare provider may advise undergoing an ESR test. This test evaluates how rapidly red blood cells settle at the bottom of a tube, with a high settling rate indicating heightened inflammation.
Who should get tested?
An ESR test is recommended for individuals having symptoms of a condition causing inflammation, such as:
- Head aches
- Unexplained fever
- Weight loss
- Stiffness in the joints
- Neck or shoulder pain
- Loss of appetite
- Anemia
When is the ESR blood test ordered?
The primary purpose of conducting an ESR test is to identify elevated levels of inflammation within the body.
The ESR test is used for the diagnosis of conditions that cause inflammation, such as:
- Temporal arteritis (inflammation of blood vessels around the scalp)
- Autoimmune diseases
- Cancers
- Infections
The ESR test is used by healthcare professionals to monitor autoimmune inflammatory conditions, including:
- Rheumatoid arthritis (chronic inflammatory disease affecting joints)
- Systemic lupus erythematosus (chronic disease causing inflammation in connective tissues)
How does the ESR blood test work?
The rate at which your red blood cells (RBCs) settle to the bottom of a test tube is measured by an ESR test. The blood sample is observed for one hour during this test.
The presence of inflammation can affect your red blood cells (RBCs). The RBCs tend to stick to one another, leading to the formation of clumps. As a result, this clumping significantly affects the speed at which the RBCs descend in a tube.
Furthermore, if you are experiencing an acute infection or chronic inflammation, the concentration of proteins in your red blood cells (RBCs) may be elevated. As a result, the cells tend to settle more rapidly. The greater the distance and speed at which the cells descend towards the bottom of a test tube, the stronger the indication of inflammation.
Types of ESR tests
Your erythrocyte sedimentation rate can be determined using one of the two methods:
- Westergren method: This particular ESR method is widely used. A Westergren-Katz tube is filled with blood up to a height of 200 millimeters (mm). The tube is then placed vertically and left at room temperature for one hour. The test measures the distance between the upper end of the blood sample and the top layer of RBC sedimentation.
- Wintrobe method: This method is similar to the Westergren method, except that a thinner 100 mm long tube is used. However, one drawback of this approach is its reduced sensitivity when compared to the Westergren method.
Interpreting the ESR test results
The ESR is measured in millimeters per hour (mm/h) and indicates the rate at which red blood cells in a sample settle towards the bottom of a test tube. Factors such as age, gender, and other variables can affect the test results. The interpretation of ESR results is personalized, considering an individual's specific circumstances, symptoms, and the results of other diagnostic tests.
An elevated ESR indicates that the red blood cells (RBCs) have sedimented at a faster rate than expected. This typically occurs when the red blood cells contain a higher amount of protein.
Numerous factors can contribute to an increase in ESR levels. Primarily, an elevated ESR is commonly associated with inflammatory conditions; however, it can also be attributed to various other health issues. Some conditions that may lead to an unusually high ESR include:
- Infections
- Lupus and rheumatoid arthritis
- Anemia
- Kidney disease
- Thyroid disease
- Some types of cancer
- Tissue injury or trauma
It is possible for the ESR to fall below the expected level, which could be attributed to certain conditions, such as:
- RBC disorders
- Heart failure
- Some liver and kidney problems
The ESR test plays a critical role in the timely identification of inflammatory diseases by measuring the rate at which red blood cells settle in a test tube over a specific time frame. This test by itself cannot diagnose any medical condition; therefore, it is crucial to complement the ESR test with other diagnostic tests in order to identify and monitor health issues effectively. This test acts as a valuable indicator of underlying inflammation in the body, assisting in the swift diagnosis and management of conditions like rheumatoid arthritis, systemic lupus erythematosus, and infections. By closely monitoring changes in ESR levels, healthcare providers can intervene early, enabling prompt initiation of treatment and improving patient outcomes.
