What does an elevated Erythrocyte Sedimentation Rate (ESR) indicate?

Elevated ESR: Clinical Significance and Interpretation

An elevated Erythrocyte Sedimentation Rate (ESR) indicates the presence of an inflammatory process in the body, serving as a nonspecific marker that can be associated with infections, autoimmune conditions, malignancies, or other inflammatory disorders. 1, 2

Normal Values and Interpretation

• Normal ESR values are typically <20 mm/h in men and <30 mm/h in women, with values increasing with age 3
• Moderate elevation (50-100 mm/h) suggests significant underlying disease, while values >100 mm/h have high specificity (92.2%) for serious conditions 1
• ESR values >100 mm/h have approximately 90% predictive value for serious underlying disease, most commonly infection, collagen vascular disease, or metastatic tumor 4

Common Causes of Elevated ESR

Infectious Causes (Most Common - 36.6% of cases with ESR ≥100 mm/h)

• Bacterial infections, particularly pulmonary infections (58% of infectious causes with extremely elevated ESR) 5
• Osteomyelitis and septic arthritis can cause significant ESR elevations 2
• In diabetic foot infections, ESR >70 mm/h increases likelihood of underlying osteomyelitis 2

Hematologic and Oncologic Causes (29.6% of cases with ESR ≥100 mm/h)

• Hematopoietic stem cell diseases (45.7% of hematologic causes) 5
• Lymphocyte and plasma cell disorders (37% of hematologic causes) 5
• Metastatic malignancies 4

Autoimmune/Inflammatory Causes (17.2% of cases with ESR ≥100 mm/h)

• Diffuse connective tissue diseases (75.7% of autoimmune causes with extremely elevated ESR) 5
• Giant cell arteritis - ESR >40 mm/h has 93.2% sensitivity; ESR >100 mm/h has 92.2% specificity 1
• Polymyalgia rheumatica - most common new-onset rheumatic disease causing elevated ESR in patients without prior rheumatic disease 6
• Rheumatoid arthritis 6
• Inflammatory bowel disease 2

Other Causes

• Renal failure 5
• Anemia (can artificially elevate ESR values) 1, 5

Factors Affecting ESR Values

• Age: ESR increases with age; elderly patients have higher baseline values 7
• Gender: Women typically have higher baseline ESR values than men 1, 3
• Anemia: Negative correlation with red blood cell count, hemoglobin, and hematocrit 5
• Positive correlation with fibrinogen levels 5

Clinical Significance and Diagnostic Approach

• ESR should not be used to screen asymptomatic persons for disease 4
• ESR lacks sensitivity and specificity when used alone as a diagnostic tool 3
• In asymptomatic persons with markedly elevated ESR, a minimal number of tests usually reveal the cause 4
• If an increased ESR is encountered with no apparent explanation, clinicians should repeat the test in several months rather than pursue an exhaustive search for occult disease 4
• ESR may be useful as a "sickness index" in elderly persons with nonspecific health changes and moderate probability of underlying disease 4

Diagnostic Value in Specific Conditions

• Giant cell arteritis: ESR >40 mm/h has high sensitivity (93.2%) with a negative likelihood ratio of 0.18 1
• Polymyalgia rheumatica: ESR is a common finding and prognostic factor 1
• Kawasaki disease: ESR often above 40 mm/h and commonly reaches levels of at least 100 mm/h 1
• Osteomyelitis in diabetes-related foot infections: ESR ≥70 mm/h has sensitivity and specificity of 81% and 80%, respectively 1

Complementary Testing

• C-reactive protein (CRP) measurement often correlates with ESR but may rise and fall more rapidly with changes in inflammation 1, 3
• Complete blood count to assess for anemia, leukocytosis, or other hematologic abnormalities 1, 3
• Extraordinarily high CRP levels with nonspecific clinical findings should raise suspicion for infections or malignancies 6

Monitoring Disease Activity

• ESR is particularly useful in monitoring conditions such as giant cell arteritis, polymyalgia rheumatica, and certain inflammatory disorders 1, 3
• Regular monitoring of ESR is recommended to assess treatment response in inflammatory conditions 3

Remember that while an elevated ESR indicates inflammation, the test itself doesn't identify the specific cause, and clinical correlation is essential for proper diagnosis and management.