Erythrocyte sedimentation rate (ESR)

What is the ESR (Erythrocyte Sedimentation Rate) test? 

The ESR blood test (Erythrocyte Sedimentation Rate) measures the speed at which red blood cells settle in a blood sample one hour after collection. In a healthy individual, red blood cells clump together and settle slowly to the bottom of a cooled test tube. However, during an infection, the sedimentation rate increases significantly due to the body's production of more proteins. 

ESR test results are helpful for diagnosing inflammatory conditions. An increased sedimentation rate almost always indicates an illness, but further tests are usually performed for an accurate diagnosis. 

ESR Test – Indications 

The ESR blood test is conducted as part of routine preventive tests ordered by a doctor. It may also be performed when a specialist suspects a condition: 

• of inflammatory origin (both acute and chronic), rheumatologic, autoimmune, or even cancer-related; 

• kidney, due to symptoms like frequent urination or changes in the smell and color of urine; 

• liver, due to symptoms such as abdominal pain. 

An indication for the ESR test is also a confirmed inflammatory condition requiring monitoring. 

How to Prepare for the ESR Test? 

The ESR blood test will provide accurate results only if you prepare for it properly. 

• Avoid alcohol and limit the intake of coffee and tea for 2-3 days before the test. 

• Refrain from eating for at least 12 hours before the test. Arrive for the ESR blood test on an empty stomach, but you may drink a glass of water in the morning. 

• Minimize stress and avoid physical exertion, including climbing stairs, as this may affect the ESR test result. 

• Blood collection should be done before taking morning medications, unless advised otherwise by your doctor. 

• Before the test, the patient should rest for 10–15 minutes (seated position). 

ESR Test – Procedure 

• The ESR test involves an invasive procedure - blood is collected into an EDTA tube. The procedure includes skin disinfection, application of a tourniquet, and pressure at the collection site. 

• Blood is collected in the morning. 

• Duration of the test: a few to several seconds. 

• Proper preparation is crucial for the ESR test to yield reliable results.