An erythrocyte sedimentation rate (ESR) test is useful for measuring inflammation in the body. Healthcare providers rely on it, along with other tests, to identify an inflammatory condition or keep track of an existing condition such as arthritis.
What is an Erythrocyte Sedimentation Rate (ESR)?
The ESR test measures how quickly your red blood cells (RBCs) settle at the bottom of a test tube. The blood sample is monitored for an hour.
When you have inflammation, it can also affect your red blood cells. At first, your RBCs may stick together in clumps. The clumping of cells makes them heavier, so they sink more quickly. Additionally, in cases of acute or chronic inflammation, there might be an increased amount of protein in your RBCs. Proteins cause your RBCs to clump together and settle faster. The deeper and quicker the cells settle at the bottom of a test tube, the higher the likelihood of inflammation being present.
Your ESR result depends on the rate at which your RBCs settle at the bottom of the test tube. If you have more inflammation in your body, the faster it will fall and the higher your ESR level will be.
Under What Conditions Is an ESR Blood Test Requested?
While an ESR test can measure inflammation in your body, it may not provide specific details about the root cause of the inflammation. For this reason, healthcare providers often use additional tests such as the C-reactive protein (CRP) test alongside the ESR test to identify the underlying reason for your symptoms. If you already have a diagnosis of an inflammatory condition, your healthcare provider may use an ESR test to monitor the progress of your treatment.
The ESR test is typically recommended for:
- Identifying the causes of inflammation, such as:
- Temporal arteritis (inflammation of blood vessels)
- Autoimmune diseases
- Infections
- Muscle or connective tissue problems
- Cancers
- Monitoring autoimmune inflammatory conditions, such as:
- Rheumatoid arthritis (RA)
- Systemic lupus erythematosus (SLE)
What Are the Symptoms That Suggest the Necessity of an ESR Test?
If you are experiencing symptoms of a condition that causes inflammation, it is advisable to undergo an ESR test. Common symptoms include:
- Headaches
- Unexplained fever
- Weight loss
- Stiffness in the joints
- Neck or shoulder pain
- Loss of appetite
- Anemia
ESR Test Preparation
No special preparation is necessary for the ESR test. It is important to let your healthcare provider know about any medications you are using. They might recommend temporarily stopping them before the test. Certain medications, like nonsteroidal anti-inflammatory drugs (NSAIDs), steroids, and statins, can affect ESR test results and lead to falsely low ESRs. However, do not stop taking any prescribed medications unless instructed by your healthcare provider.
ESR Test Procedure
The procedure starts with cleaning the skin over your vein. Next, a needle is used to draw your blood. Once the blood is collected, the needle is taken out and the puncture site is covered to prevent bleeding.
After your blood sample is taken to the lab, it will be placed in a long, thin tube for one hour. The laboratory professional will then determine how far your RBCs sink into the tube, how rapidly they sink, and the number of RBCs sinking during and after this hour.
When there is inflammation, it can lead to the presence of unusual proteins in your blood. These proteins are responsible for making your RBCs stick together, which makes them settle faster.
ESR Test Result Interpretation
A higher erythrocyte sedimentation rate suggests a greater likelihood of inflammation. Generally, women tend to have naturally higher ESR levels.
|
Normal ESR test result ranges |
Deviant ESR test results |
|
|
Females under 50 |
0 –20 mm/hr. |
> 20 |
|
Males under 50 |
0 –15 mm/hr. |
> 15 |
|
Females over 50 |
0 –30 mm/hr. |
> 30 |
|
Males over 50 |
0 –20 mm/hr. |
> 20 |
|
Children |
0 –10 mm/hr. |
> 10 |
If the ESR test results are greater than 100 mm/hr, it could be a sign of a more "active" disease, such as diabetes, cardiovascular disease, or cancer.
Causes and Implications of High ESR Levels
An elevated ESR level suggests that the red blood cells have settled more quickly than usual, which can happen when they have a higher protein content.
Several factors can contribute to elevated ESR levels. While it is commonly linked to inflammation, it can also be a sign of other health conditions. An increase in the ESR above the normal level may be attributed to certain conditions, such as:
- Infections (bone, heart, or skin infections)
- Lupus and rheumatoid arthritis
- Kidney disease
- Thyroid disease
- Anemia
- Certain types of cancer (lymphoma, multiple myeloma)
- Tissue injury or trauma
- Pregnancy
- Diabetes
- Obesity
A decrease in the ESR below the normal level may be attributed to specific conditions, such as:
- RBC disorders
- Heart failure
- Liver and kidney problems
The ESR test is helpful for detecting inflammation in the body, which can aid in diagnosing and managing conditions such as rheumatoid arthritis, systemic lupus erythematosus, and infections. Monitoring ESR levels allows healthcare providers to intervene quickly, start treatment promptly, and improve patient outcomes.
