What is the significance of Erythrocyte Sedimentation Rate (ESR)?

From the Guidelines

The Erythrocyte Sedimentation Rate (ESR) is a significant non-specific inflammatory marker that serves as an important screening tool for detecting inflammation, infection, and certain diseases in the body.

Importance of ESR

The ESR test measures how quickly red blood cells settle in a test tube over one hour, and when inflammation is present, proteins like fibrinogen increase in the blood, causing red blood cells to stick together and settle more quickly, resulting in an elevated ESR.

• This test is particularly valuable for diagnosing and monitoring conditions such as rheumatoid arthritis, temporal arteritis, polymyalgia rheumatica, and certain infections.
• ESR is also useful for tracking disease progression and treatment response over time.
• However, since it's non-specific, an elevated ESR alone cannot diagnose a particular condition and must be interpreted alongside clinical symptoms and other laboratory tests.

Clinical Application

Normal ESR values typically range from 0-15 mm/hr for men and 0-20 mm/hr for women, with values increasing with age.

• The test is simple, inexpensive, and widely available, making it a practical first-line investigation despite newer inflammatory markers like C-reactive protein (CRP) being available.
• According to a study published in the Annals of the Rheumatic Diseases 1, ESR and CRP should be performed at baseline in the investigation for diagnosis and prognosis of undifferentiated peripheral inflammatory arthritis.
• Another study published in Circulation 1 suggests that ESR is a useful marker for detecting inflammation in patients with Kawasaki disease.
• A study published in the Annals of the Rheumatic Diseases 1 found that a higher ESR was associated with a higher relapse rate in patients with polymyalgia rheumatica.
• The American College of Rheumatology recommends using ESR as part of a composite measure of disease activity in patients with rheumatoid arthritis 1.
• The choice of ESR as a measure of disease activity should be influenced by comorbidities, patient factors, and drug-related risks 1.

From the Research

Significance of ESR

The erythrocyte sedimentation rate (ESR) is a marker of inflammatory conditions and has been used extensively by clinicians in both outpatient and inpatient settings 2. The significance of ESR can be understood from the following points:

• ESR is an indirect measure of fibrinogen, which has a longer half-life than C-reactive protein (CRP), making ESR helpful in monitoring chronic inflammatory conditions 2.
• ESR and CRP can be complementary to good history taking and physical examination in the diagnosis and monitoring of inflammatory conditions, but they should be used wisely due to factors that can result in falsely high or low levels 2.
• ESR and CRP have a modest positive correlation with each other, but they are weakly correlated with disease activity measures in patients with rheumatoid arthritis, systemic lupus erythematosus, and osteoarthritis 3.

Clinical Applications of ESR

The clinical applications of ESR can be summarized as follows:

• ESR is widely used as a laboratory marker of systemic inflammation, but it lacks sensitivity and specificity, and should be used only in combination with clinical history and physical exam for diagnosis and monitoring of pathological conditions 4.
• ESR can be useful in monitoring chronic inflammatory conditions, whereas CRP is more useful in diagnosis and monitoring responses to therapy in acute inflammatory conditions 2.
• Extremely high ESR (≥ 100 mm/h) can be a valuable clinical parameter in diagnosing and managing rheumatic diseases, and can be associated with newly diagnosed rheumatic disease, disease flare-up, or coexisting infection 5.

Comparison with CRP

The comparison between ESR and CRP can be summarized as follows:

• ESR and CRP have different half-lives, with ESR being an indirect measure of fibrinogen, which has a longer half-life than CRP 2.
• ESR and CRP can have discordant measurements, which can be due to various physiological factors, including noninfectious conditions and resolution of inflammation 4.
• High-sensitivity CRP (hsCRP) levels can be used to distinguish between infection and disease flare in patients with systemic lupus erythematosus, with a cut-off of above 5 mg/dl having a specificity of 80% for infection 6.