Definition

The erythrocyte sedimentation rate (ESR) test measures the rate at which red blood cells settle at the bottom of a test tube. Under normal circumstances, red blood cells do not settle quickly. However, in the presence of certain conditions such as inflammation or infection, red blood cells settle at an accelerated rate. Various factors, such as inflammation and infection, can influence the speed at which red blood cells settle.

When inflammation or infection occurs, red blood cells change in shape and tend to stick together, forming clumps. Additionally, the inflammation increases the amount of protein in the blood, causing the red blood cells to become heavier and settle more quickly. The faster the red blood cells settle, the higher the ESR. This test is primarily used to detect the presence of inflammation and infection, although it cannot provide a definitive diagnosis of a specific disease. ESR is also helpful for monitoring chronic inflammatory conditions.

Indication

An ESR test is necessary if you experience symptoms of inflammation, such as:

• Fever

• Headache

• Joint swelling or stiffness

• Joint pain

• Neck or shoulder pain

• Weight loss

• Decreased appetite

• Diarrhea, bloody stools, and abdominal pain

• To monitor chronic inflammatory conditions such as lupus, rheumatoid arthritis, vasculitis (inflammation of the blood vessels), and polymyalgia rheumatica

Contraindication

There are no specific contraindications for the erythrocyte sedimentation rate test.

Preparation Before the Test

No special preparation is required for the ESR test. You do not need to fast before undergoing the test. However, it is recommended to consult your doctor prior to the test, as certain conditions or medications may affect the results and lead to inaccurate readings.

Conditions and medications that can influence ESR results include:

• Pregnancy, menstruation, or anemia, as these conditions can cause the ESR to be in the moderate range.

• Steroid drugs, anti-inflammatory medications, pain relievers, birth control pills, and cholesterol-lowering drugs may cause a lower ESR.

• The consumption of supplements and vitamins, such as vitamin A, can also affect ESR results.

Test Procedure

The ESR test typically requires a blood serum sample of 0.25-0.5 mL. This sample is drawn from a vein and placed into a specialized tube. Laboratory personnel will wear gloves and personal protective equipment (PPE) when collecting the sample.

Before drawing the blood, the technician will apply an elastic band to your arm and clean the puncture site with antiseptic gauze. Blood is usually collected from a vein in the crease of the elbow. After the blood is drawn and placed into the test tube, the elastic band will be removed, and the puncture site will be cleaned again. The procedure takes only a few minutes. The blood sample will then be analyzed in the laboratory, and the results can be available within a few hours. The sedimentation rate of the red blood cells is measured over the course of one hour, and the results are expressed in millimeters per hour (mm/hr).

Normal and Abnormal Values

The erythrocyte sedimentation rate (ESR) is measured in millimeters per hour (mm/hour). The normal values for ESR vary depending on age and gender, as shown in the table below:

It is important to note that the normal ESR values may slightly vary between laboratories due to differences in guidelines and testing methods.

Results and Recommendations (Follow-up Tests)

Normal Results

If your ESR results fall within the normal range, it suggests that there is likely no inflammation or infection in the body, assuming there are no specific symptoms or clinical signs present.

In this case, maintaining a healthy lifestyle is recommended to prevent inflammation or infection that could increase ESR levels in the future.

High Results

Elevated ESR results are often associated with various medical conditions, including inflammatory diseases such as lupus, rheumatoid arthritis, vasculitis (inflammation of the blood vessels), chronic infections (e.g., tuberculosis, bone infections, heart infections, skin infections), and malignancies. While the ESR test indicates the presence of inflammation or infection, it cannot provide a definitive diagnosis. Therefore, further tests, such as a complete blood count (CBC), C-reactive protein (CRP) tests, autoimmune marker tests, X-rays (e.g., lung or heart), or malignancy markers, may be necessary to pinpoint the exact cause of the inflammation or infection.

Low Results

A low ESR resylts can be seen in conditions such as heart failure, polycythemia vera (a type of blood cancer), leukocytosis (increased white blood cells), and sickle cell anemia. To investigate these conditions further, your doctor may recommend additional tests such as chest X-rays, a complete blood count, iron profiles, and peripheral blood smears.

Consult the Right Doctor

If you have abnormal ESR test results, you should consult a general practitioner for further evaluation or to initiate appropriate treatment based on the diagnosis. You may also consult an internist or infection specialist for a more detailed discussion of your ESR results. In the case of pediatric patients, any abnormal results should be discussed with a pediatrician.

Looking for more information about laboratory, radiology, and other examination results? Click here!