Erythrocyte Sedimentation Rate
- Sample Type
- Whole Blood
- Fasting
- No
- Unit
- mm/hr
Function
The Erythrocyte Sedimentation Rate (ESR) is a common hematology test that measures how quickly red blood cells (erythrocytes) sink to the bottom of a tall, thin vertical tube. Under normal conditions, RBCs fall slowly. However, when inflammation is present in the body, certain proteins (like fibrinogen and globulins) cause RBCs to clump together into 'rouleaux' formations. These clumps are heavier than individual cells and sediment much faster, resulting in a higher ESR value.
Why it is Ordered
Physicians order an ESR when they suspect an inflammatory condition but need to confirm the presence of systemic activity. It is frequently used to monitor the progression or treatment efficacy of chronic inflammatory diseases. Common reasons for the test include unexplained fever, joint pain, muscle stiffness, or persistent headaches that might suggest temporal arteritis. It is often paired with the C-Reactive Protein (CRP) test for a more comprehensive inflammatory profile.
Associated Conditions
A high ESR is associated with a wide variety of conditions, which can be categorized into:
- Autoimmune Diseases: Rheumatoid arthritis, Systemic Lupus Erythematosus (SLE), and Polymyalgia Rheumatica.
- Infections: Bacterial infections (endocarditis, osteomyelitis) and tuberculosis.
- Malignancies: Multiple myeloma, lymphomas, and various metastatic cancers.
- Tissue Damage: Myocardial infarction (heart attack) or major trauma.
Check Your Result
Check Your Result
Enter your lab result to see where you stand compared to the standard reference range.
Why Context Matters
The ESR is a highly non-specific marker and can be influenced by many factors unrelated to inflammation. A second opinion or follow-up testing is often necessary because results can be skewed by anemia (which artificially increases ESR), pregnancy, obesity, and advancing age. Furthermore, certain medications like oral contraceptives or aspirin can cause fluctuations. Because it reflects changes in plasma proteins slowly, it may not immediately reflect the onset of an acute infection, requiring clinical correlation.
Lab ranges are statistical averages, not biological laws. "Normal" for a 20-year-old male isn't normal for a 60-year-old female.
Clinical References
Source-of-truth databases and clinical guidelines for Erythrocyte Sedimentation Rate:
Official Sources
- Clinical Practice Guidelines | American College of Rheumatologyrheumatology.org
Research & Guidelines
Related Indicators
Medically Reviewed by Dr. Binoy Babu, MBBS
Board Certified Doctor • 10+ Years Clinical Experience
Dr. Babu is a practicing physician dedicated to empowering patients with clear, actionable medical information. He founded 2opi to bridge the gap between complex lab reports and patient understanding, ensuring everyone has access to a reliable second opinion.
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