What Is an ESR Test?
An erythrocyte sedimentation rate (ESR) test does not diagnose one specific condition. Instead, it helps your doctor determine whether you are experiencing inflammation. The doctor will look at ESR results along with other information or test results to help figure out a diagnosis. Which tests are ordered will depend on your symptoms. This test can also be used to monitor inflammatory diseases.
In this test, a sample of your blood is placed in a tall, thin tube. The speed at which the red blood cells fall to the bottom of the tube is measured. Inflammation can cause abnormal proteins to appear in your blood. These proteins cause your red blood cells to clump together. This makes them fall more quickly.
This test is sometimes called a sed (or sedimentation) rate test.
Why Doctors Perform an ESR Test
Your doctor may order an ESR test to help detect inflammation in your body. This can be useful in diagnosing conditions that cause inflammation, such as autoimmune diseases, cancers, and infections.
An ESR test can be used to monitor inflammatory conditions, such as rheumatoid arthritis or systemic lupus erythematosus. Your doctor might also order this test if you are experiencing some types of arthritis, fevers, and muscle problems.
The ESR test is rarely performed alone. Instead, it will be combined with other tests to determine the cause of your symptoms.
Preparing for the ESR Test
Many different medications and drugs can affect your ESR levels. These include:
- aspirin (in high doses)
- salicylate (in high doses)
Tell your doctor if you are taking any medications. You will be told whether you should temporarily stop taking them before the test.
The ESR Test
All this test involves is a blood draw. The skin directly over a vein will be cleaned, and a needle will be inserted to collect your blood. After the blood has been collected, the needle will be removed, and the site of the puncture will be covered to stop any bleeding. It should take only a minute or two.
Risks of the ESR Test
Having your blood drawn involves only minimal risks. Possible complications include:
- excessive bleeding
- hematoma (bruising)
- inflammation of the vein
You will probably feel mild to moderate pain when the needle is inserted. You might also feel throbbing after the needle has been removed.
Normal ESR Test Results
ESR test results are measured in mm/hr, or millimeters per hour.
Normal results are generally:
- women under 50: under 20 mm/hr
- men under 50: under 15 mm/hr
- women over 50: under 30 mm/hr
- men over 50: under 20 mm/hr
- newborns: under 2 mm/hr
- children before puberty: 3 to 13 mm/hr
What Do Abnormal ESR Test Results Mean?
An abnormal ESR result does not diagnose any particular disease. It just identifies any inflammation in your body.
This test is not always reliable or meaningful. According to Harvard Health, abnormal test results don’t always mean you have a disease (HHP, 2003). Many factors, such as age or medication use, can alter your results.
In addition, abnormal results don’t tell your doctor what is actually wrong. Instead, they indicate a need to look further. Your doctor will usually order follow-up tests if your ESR results are too high or low.
High ESR Rates
There are multiple causes of high ESR rates. Some common conditions associated with high rates include:
- kidney disease
- multiple myeloma
- old age
- temporal arteritis
- thyroid disease
- Waldenstrom’s macroglobulinemia
ESR rates that are higher than normal are also associated with autoimmune disorders such as:
- systemic lupus erythematosus
- rheumatoid arthritis
- giant cell arteritis
- polymyalgia rheumatica
- primary macroglobulinemia
- too much fibrinogen in your blood (hyperfibrinogenemia)
- vasculitis, allergic or necrotizing
Some types of infection that cause ESR rates to become higher than normal are:
- bone infection
- heart infection
- heart valve infection
- rheumatic fever
- skin infection
- systemic infection
Low ESR Rates
Low ESR rates may be caused by:
- congestive heart failure
- low plasma protein
- sickle cell anemia
Some causes of abnormal ESR rates are more serious than others, but many are not a huge deal. That’s why it’s important not to worry too much just because your ESR levels are abnormal. Instead, work with your doctor to find out what’s causing your symptoms.