ESR (Sed Rate)
Measures inflammation levels by testing how quickly red blood cells settle in a tube over one hour.
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What this test measures
The erythrocyte sedimentation rate (ESR) is a straightforward blood test that measures how quickly red blood cells settle to the bottom of a vertical tube over one hour. Under normal conditions, red blood cells settle slowly. When inflammation is present, the liver produces elevated levels of certain proteins (particularly fibrinogen) that cause red blood cells to clump together. These clumps are heavier than individual cells and drop faster, producing a higher sedimentation rate.
The ESR is a nonspecific marker, meaning it indicates that inflammation exists somewhere in the body without pointing to a particular organ or disease. Elevated readings can accompany a wide range of conditions including infections, autoimmune diseases, malignancies, and tissue injury. Despite this lack of specificity, the ESR is particularly useful for tracking chronic inflammatory conditions over time: rising values may suggest disease progression, while declining values often correlate with treatment response or remission.
Who should consider this test
You might consider this test if you are experiencing any of the following:
- Individuals experiencing unexplained fatigue, fever, joint pain, or muscle aches that may suggest inflammatory conditions
- Those with known autoimmune disorders like rheumatoid arthritis, lupus, or inflammatory bowel disease who need monitoring
- Patients suspected of having infections, particularly when other symptoms are present but the cause is unclear
- Individuals being evaluated for conditions like temporal arteritis, polymyalgia rheumatica, or other inflammatory disorders
- Those undergoing treatment for inflammatory conditions who need to track response to therapy over time
What to expect
Preparation
No special preparation is needed for an ESR test - individuals can eat, drink fluids and take usual medications and supplements. Certain factors like pregnancy, menstrual cycle, medications, and recent fatty meals may affect results, so inform your healthcare provider about any relevant circumstances.
Sample Type
A small amount of blood is drawn from a vein, usually in the arm, using a needle inserted into the vein. The blood collection process typically takes less than five minutes.
Collection
A healthcare provider or phlebotomist will clean the area with antiseptic and insert a needle into the vein to collect the blood sample. Individuals may feel a slight sting when the needle goes in or out.
Turnaround
Results are typically available within 24-48 hours after the sample is collected at the laboratory.
Understanding your results
Results are reported in millimeters per hour (mm/hr). The ESR cannot confirm or rule out any specific disease; it functions as a general indicator of inflammatory activity that healthcare providers use alongside other laboratory tests, imaging, physical examination, and reported symptoms to build a clinical picture. An elevated ESR prompts further investigation to identify the source and cause of inflammation, while a normal result makes significant systemic inflammation less likely, though it does not exclude it entirely.
| Population | Reference Range | Notes |
|---|---|---|
| Men under 50 | 0-15 mm/hr | Normal range for adult males under 50 years of age |
| Women under 50 | 0-20 mm/hr | Normal range for adult females under 50 years of age |
| Men over 50 | 0-20 mm/hr | Slightly higher normal range for older adult males |
| Women over 50 | 0-30 mm/hr | Higher normal range for older adult females |
Reference ranges shown are general guidelines. Your lab report will include the specific reference range used by the laboratory that processed your sample, which is the authoritative range for interpreting your results.
What does a “Low” result mean?
Decreased ESR may occur in conditions like polycythemia, hyperviscosity, sickle cell anemia, leukemia, chronic fatigue syndrome, or low plasma protein due to liver or kidney disease. High blood viscosity and increased red blood cell count can slow the settling rate. Certain blood disorders like sickle-cell disease can result in low ESR due to improper red blood cell shape that impairs normal stacking. While low ESR is less commonly a cause for concern, it may occasionally indicate underlying blood disorders that affect red blood cell characteristics.
What does a “High” result mean?
Elevated ESR levels may suggest increased inflammatory activity and can occur in conditions including acute and chronic infections, autoimmune diseases such as connective tissue disorders, malignancies, and tissue injury or necrosis. ESR values exceeding 100 mm/hr carry a 90% probability of serious underlying disease and warrant urgent medical evaluation. Mildly elevated ESR may also result from non-disease factors like anemia, pregnancy, obesity, menstruation, or recent minor illness. Healthcare providers typically consider clinical symptoms and order additional tests to determine the underlying cause of elevated results.
Privacy & confidentiality
All test orders are authorized and results reviewed by an independent, board-certified physician who is not the patient's personal doctor. Your ESR test results are handled with complete confidentiality and privacy protection. All test results are <u>not reported to your doctor</u> unless you specifically choose to share them, giving you full control over your health information. The results are <u>not part of your medical records</u> and won't appear in any medical databases or insurance systems. Additionally, ESR test results are <u>not on insurance statements</u> or explanation of benefits forms, ensuring your privacy is maintained. LevelPanel maintains strict data security protocols and never shares your personal health information with employers, insurance companies, or third parties without your explicit consent. You can access your results through a secure online portal, and no doctor visit is required to order this test. This confidential testing approach allows individuals to monitor their inflammation levels privately and make informed decisions about their health without external pressures or concerns about insurance implications.
Frequently asked questions
Related tests
C-Reactive Protein (CRP)
Often ordered together with ESR as CRP responds more quickly to acute inflammation and provides complementary information
View TestComplete Blood Count (CBC)
Helps evaluate for anemia and other blood conditions that can affect ESR results
View TestRheumatoid Factor (RF)
Used to help diagnose rheumatoid arthritis and other autoimmune conditions when ESR is elevated
View TestRelated conditions
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Last reviewed: April 2026
CPT Code: 85652
This test may not be available in: NY, NJ, RI
This page is for informational purposes only and does not constitute medical advice. Always consult with a healthcare provider regarding any health concerns. LevelPanel does not diagnose, treat, or prescribe.
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LevelPanel has no business or affiliate relationship with Quest or LabCorp. These links are provided as a public service.
Lab testing services linked from this site are not available to residents of Alaska, Arizona, or Hawaii, unless otherwise noted on the lab's own website.
This publication is not intended to solicit the purchase of laboratory testing from any individual consumer.
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