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Erythrocyte sedimentation rate (ESR) measured in plasma using bromocresol green method

Published: August 9, 2026Updated: August 16, 2026

This test measures how quickly red blood cells settle in plasma, which can help identify inflammation in your body.

Quick summary

["ESR helps doctors check for conditions like infections, autoimmune diseases, or other inflammatory processes."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
85329-1
Short code
ER+ cells NFr Br ca spec ImStn
Synonyms
ER+ cells NFr Br ca spec ImStn
Category
coagulation
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
immune-stain
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

What Is Erythrocyte Sedimentation Rate (ESR)?

ESR measures the rate at which red blood cells (erythrocytes) fall to the bottom of a tube over time. When inflammation is present, the plasma proteins around red blood cells become more sticky, causing them to settle faster. This test is often used as a general screening tool for conditions that cause inflammation.

Why Might Your Doctor Order This Test?

Your doctor may order an ESR to monitor conditions such as rheumatoid arthritis, lupus, infections, or other inflammatory diseases. It can also be used to check how your body is responding to treatment for these conditions.

How Is This Test Performed?

A small amount of your blood is drawn and placed in a test tube with an anticoagulant to prevent clotting. The tube is then tilted to allow the red blood cells to settle. The time it takes for the red blood cells to form a layer at the bottom of the tube is measured and recorded.

What Does a High or Low ESR Mean?

A higher-than-normal ESR often suggests inflammation or infection. A lower ESR may indicate no inflammation or could be due to certain blood disorders or medications. However, ESR alone is not diagnostic and should be interpreted along with other clinical findings.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

ESR (Plasma, BCG)

Frequently asked questions

What causes an elevated ESR?
Elevated ESR can be caused by various factors, including infections (like pneumonia or urinary tract infections), autoimmune diseases (like rheumatoid arthritis or lupus), certain cancers, and other inflammatory conditions. Stress, pregnancy, and certain medications can also temporarily affect ESR levels.
What if my ESR is normal but I still feel unwell?
A normal ESR does not rule out all possible causes of your symptoms. If you are still experiencing concerns, your doctor may order additional tests to identify the underlying issue, such as blood tests for specific markers, imaging studies, or other diagnostic procedures.
How often should I get this test?
The frequency of ESR testing depends on your medical condition and treatment plan. If you have a chronic condition like rheumatoid arthritis, your doctor may recommend regular monitoring. If you are asymptomatic, ESR testing may not be routinely recommended unless you have specific symptoms or risk factors.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy