An erythrocyte sedimentation rate (ESR) test is sometimes called a sedimentation rate test or sed rate test. This test doesn’t diagnose one specific condition. Instead, it helps your doctor determine whether you’re experiencing inflammation. The doctor will look at ESR results along with other information or test results to help figure out a diagnosis. The tests ordered will depend on your symptoms. This test can also monitor inflammatory diseases.
In this test, a tall, thin tube holds a sample of your blood. 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.
An ESR test can monitor inflammatory conditions, such as rheumatoid arthritis or systemic lupus erythematosus. Your doctor might also order this test if you’re experiencing fevers, some types of arthritis, or certain muscle problems.
The ESR test is rarely performed alone. Instead, your doctor will combine it with other tests to determine the cause of your symptoms.
Many different medications and drugs affect your ESR test results. These include:
- androgens, such as testosterone
- aspirin or other salicylates, when taken in high doses
- valproic acid (Depakene)
- divalproex sodium (Depakote)
- phenytoin (Dilantin)
Tell your doctor if you’re taking any medication. Your doctor may ask you to temporarily stop taking medication before the test.
This test involves a blood draw. First, the skin directly over your vein is cleaned. Then, a needle is inserted to collect your blood. After collecting your blood, the needle will be removed and the puncture site will be covered to stop any bleeding. It should take only a minute or two.
Having your blood drawn involves has minimal risks. Possible complications include:
- excessive bleeding
- hematoma, or bruising
- inflammation of the vein
You will probably feel mild to moderate pain when the needle pricks your skin. You might also feel throbbing at the puncture site after the test.
ESR test results are measured in mm/hr, or millimeters per hour.
The following are considered normal ESR test results:
- Women under age 50 should have an ESR under 20 mm/hr.
- Men under age 50 should have an ESR under 15 mm/hr.
- Women over age 50 should have an ESR under 30 mm/hr.
- Men over age 50 should have an ESR under 20 mm/hr.
- Newborns should have an ESR under 2 mm/hr.
- Children who haven’t reached puberty yet should have an ESR between 3 and 13 mm/hr.
An abnormal ESR result doesn’t diagnose any particular disease. It just identifies any inflammation in your body.
This test isn’t always reliable or meaningful. Many factors, such as age or medication use, can alter your results.
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 Test Results
There are multiple causes of a high ESR test result. Some common conditions associated with high rates include:
- kidney disease
- multiple myeloma
- old age
- temporal arteritis
- thyroid disease
- Waldenstrom’s macroglobulinemia
- certain types of arthritis
ESR test results that are higher than normal are also associated with autoimmune disorders, including:
- systemic lupus erythematosus
- rheumatoid arthritis
- giant cell arteritis
- polymyalgia rheumatica
- primary macroglobulinemia
- too much fibrinogen in your blood, or hyperfibrinogenemia
- allergic or necrotizing vasculitis
Some types of infection that cause ESR test results to become higher than normal are:
- bone infection
- heart infection
- heart valve infection
- rheumatic fever
- skin infection
- systemic infection
Low ESR Test Results
A low ESR test result may be due to:
- congestive heart failure
- low plasma protein
- sickle cell anemia
Some causes of abnormal ESR test results are more serious than others, but many aren’t a huge concern. It’s important not to worry too much if your ESR test results are abnormal. Instead, work with your doctor to find out what’s causing your symptoms.