What is the erythrocyte sedimentation rate test. How is the ESR test performed. What do high and low sed rate results indicate. When might a doctor order an ESR test. What conditions can the sed rate test help diagnose.

What is the Erythrocyte Sedimentation Rate (ESR) Test?

The erythrocyte sedimentation rate (ESR) test, commonly known as the “sed rate” test, is a simple blood test used to detect inflammation in the body. This test measures how quickly red blood cells (erythrocytes) settle at the bottom of a test tube over a period of one hour. The sed rate test is a valuable diagnostic tool that can help healthcare providers identify and monitor various inflammatory conditions.

How Does the ESR Test Work?

The ESR test works on a simple principle: when inflammation is present in the body, certain proteins in the blood cause red blood cells to clump together. These clumps are heavier than individual cells, causing them to fall (or sediment) more quickly to the bottom of the test tube. The faster the red blood cells fall, the higher the level of inflammation in the body.

Why is the ESR Test Important?

The ESR test is important because it serves as a non-specific marker of inflammation. While it cannot pinpoint the exact location or cause of inflammation, it can alert healthcare providers to the presence of an underlying condition that requires further investigation. This test is often used in conjunction with other diagnostic tools to help diagnose and monitor various diseases and conditions.

The Process of Performing an ESR Test

The ESR test is a straightforward procedure that requires minimal preparation from the patient. Here’s a step-by-step breakdown of the process:

1. Blood sample collection: A healthcare professional draws a small amount of blood from a vein in your arm.
2. Sample preparation: The blood is placed in a special tall, thin tube.
3. Sedimentation: The tube is left undisturbed for one hour, allowing the red blood cells to settle.
4. Measurement: After one hour, the distance the red blood cells have fallen is measured in millimeters.
5. Result interpretation: The healthcare provider interprets the results based on the patient’s age, gender, and other factors.

Is any special preparation required for an ESR test? Generally, no special preparation is needed. However, it’s important to inform your healthcare provider about any medications or supplements you’re taking, as some can affect the results. Additionally, if you’re pregnant or menstruating, this information should be shared as it may influence the interpretation of the results.

Interpreting ESR Test Results: What Do They Mean?

Understanding ESR test results is crucial for both healthcare providers and patients. The results are typically reported in millimeters per hour (mm/hr), indicating the distance red blood cells have fallen in one hour. Normal ranges can vary based on age and gender:

• Men under 50: 0-15 mm/hr
• Men over 50: 0-20 mm/hr
• Women under 50: 0-20 mm/hr
• Women over 50: 0-30 mm/hr

High ESR Results

What does a high ESR result indicate? A high ESR result suggests the presence of inflammation in the body. This could be due to various conditions, including:

• Infections (bacterial, viral, or fungal)
• Autoimmune disorders (such as rheumatoid arthritis or lupus)
• Certain types of cancer
• Chronic kidney disease
• Cardiovascular diseases

It’s important to note that a high ESR alone is not diagnostic of any specific condition. Further tests and clinical evaluation are typically needed to determine the underlying cause.

Low ESR Results

Can ESR results be too low? While less common, abnormally low ESR results can occur. Conditions that may cause low ESR include:

• Polycythemia (increased red blood cell production)
• Sickle cell anemia
• Congestive heart failure
• Hypofibrinogenemia (low levels of fibrinogen in the blood)

Low ESR results are generally less concerning than high results but may still warrant further investigation depending on the clinical context.

Medical Conditions Associated with Abnormal ESR Results

The ESR test can be helpful in diagnosing and monitoring a wide range of medical conditions. Some of the most common conditions associated with abnormal ESR results include:

Autoimmune Disorders

How does ESR help in diagnosing autoimmune disorders? ESR is often elevated in autoimmune conditions due to the chronic inflammation these disorders cause. Some examples include:

• Rheumatoid arthritis
• Systemic lupus erythematosus (SLE)
• Vasculitis
• Polymyalgia rheumatica

Infections

ESR can be elevated in various types of infections, including:

• Bacterial infections (e.g., pneumonia, osteomyelitis)
• Viral infections (though less commonly than in bacterial infections)
• Tuberculosis
• Endocarditis

Cancer

Certain types of cancer can cause elevated ESR levels, particularly:

• Multiple myeloma
• Lymphoma
• Metastatic cancers

Cardiovascular Diseases

ESR may be elevated in various cardiovascular conditions, such as:

• Myocardial infarction (heart attack)
• Peripheral artery disease
• Giant cell arteritis

Factors That Can Affect ESR Test Results

Several factors can influence ESR test results, potentially leading to falsely high or low readings. It’s crucial for healthcare providers to consider these factors when interpreting ESR results:

Physiological Factors

• Age: ESR tends to increase with age
• Gender: Women typically have higher ESR values than men
• Pregnancy: ESR can be elevated during pregnancy
• Menstruation: May cause a slight increase in ESR

Medical Conditions

• Anemia: Can cause falsely high ESR results
• Kidney disease: May lead to elevated ESR
• Thyroid disorders: Can affect ESR levels
• Obesity: May cause slightly higher ESR values

Medications

Certain medications can affect ESR results, including:

• Oral contraceptives
• Methyldopa
• Vitamin A
• Cortisone
• Quinine

It’s essential for patients to inform their healthcare providers about all medications and supplements they’re taking before the ESR test.

ESR vs. Other Inflammatory Markers: What’s the Difference?

While the ESR test is a valuable tool for detecting inflammation, it’s not the only test available. Other inflammatory markers are often used in conjunction with or as alternatives to ESR. Understanding the differences between these tests can help healthcare providers choose the most appropriate diagnostic tools for each situation.

C-Reactive Protein (CRP)

How does CRP compare to ESR? C-reactive protein (CRP) is another commonly used inflammatory marker. Key differences include:

• Speed of change: CRP levels change more rapidly than ESR in response to inflammation
• Specificity: CRP is more specific to acute inflammation than ESR
• Sensitivity: CRP is generally more sensitive than ESR for detecting inflammation

CRP is often used alongside ESR to provide a more comprehensive picture of inflammation in the body.

Plasma Viscosity (PV)

Plasma viscosity is another test that can be used to detect inflammation. Compared to ESR:

• PV is less affected by factors like anemia or age
• PV results are available more quickly than ESR
• PV is less widely available than ESR in many healthcare settings

Fibrinogen

Fibrinogen is a protein produced by the liver that plays a role in blood clotting and inflammation. While not as commonly used as ESR or CRP, fibrinogen levels can provide additional information about inflammatory processes in the body.

Limitations and Considerations of the ESR Test

While the ESR test is a useful diagnostic tool, it’s important to understand its limitations and consider them when interpreting results:

Non-Specificity

The primary limitation of the ESR test is its non-specificity. An elevated ESR indicates the presence of inflammation but doesn’t pinpoint its cause or location. This means that additional tests and clinical evaluation are usually necessary to reach a diagnosis.

Delayed Response

ESR changes relatively slowly in response to inflammation. It may take several days for ESR to rise after the onset of an inflammatory process and may remain elevated for weeks after the inflammation has resolved. This delay can make ESR less useful for monitoring rapid changes in a patient’s condition.

Influence of Non-Inflammatory Factors

As mentioned earlier, various factors unrelated to inflammation can affect ESR results. These include age, gender, pregnancy, and certain medications. Healthcare providers must take these factors into account when interpreting ESR results to avoid misdiagnosis.

Limited Usefulness in Certain Conditions

ESR may not be elevated in all inflammatory conditions. For example, some patients with rheumatoid arthritis or systemic lupus erythematosus may have normal ESR values despite active disease. In such cases, other tests or clinical assessments may be more informative.

The Future of Inflammatory Markers and Diagnostics

As medical science advances, new technologies and approaches are being developed to improve the diagnosis and monitoring of inflammatory conditions. While traditional tests like ESR continue to play a crucial role, emerging techniques offer the potential for more precise and personalized diagnostics.

Biomarker Panels

Researchers are developing panels of multiple biomarkers that, when measured together, can provide a more comprehensive and specific picture of inflammation in the body. These panels may combine traditional markers like ESR and CRP with newer, more specialized biomarkers.

Genetic Testing

Advances in genetic testing are allowing healthcare providers to identify genetic markers associated with increased risk or severity of certain inflammatory conditions. This information can help guide prevention strategies and treatment decisions.

Imaging Techniques

New imaging technologies, such as advanced MRI techniques and PET scans, are providing more detailed visualizations of inflammation in the body. These tools can help pinpoint the location and extent of inflammation more accurately than blood tests alone.

Artificial Intelligence and Machine Learning

The integration of artificial intelligence and machine learning algorithms into diagnostic processes is showing promise in improving the interpretation of test results and identifying patterns that may not be apparent to human observers.

As these technologies continue to develop, they will likely complement rather than replace traditional tests like ESR, enhancing healthcare providers’ ability to diagnose and manage inflammatory conditions accurately and efficiently.

ESR Test Results High vs. Low

Written by WebMD Editorial Contributors

• Why You Might Get a Sed Rate
• Taking the Blood Sample
• The Results and What They Mean
• Other Tests You May Need

The sedimentation rate — or “sed rate,” for short — is a blood test that checks for inflammation in your body. It’s one clue for your doctor that you might have a disease linked to inflammation, like arthritis or cancer, or an infection.

The sed rate test measures how fast red blood cells fall to the bottom of a tube. Inflammation creates proteins that make red blood cells fall more quickly.

Another name for this test is erythrocyte sedimentation rate (ESR). Red blood cells are called erythrocytes. Sedimentation is the process by which they fall to the bottom of the tube.

Your doctor might order the sed rate test if you have symptoms like these:

• Headaches
• Stiff, swollen, or painful joints
• Pain in your shoulders, neck, or pelvis
• Appetite loss
• Weight loss without trying

The sed rate test can be part of the process of discovering if you have one of these conditions:

• Infection (including of the bones)
• Cancer
• Arteritis (inflammation of the blood vessels)
• Lupus (an autoimmune disease that damages the skin, joints, and other parts of your body)
• Polymyalgia rheumatica (causes stiff and painful muscles)
• Rheumatoid arthritis (autoimmune disease in which the immune system attacks your joints)
• Systematic vasculitis (inflammation in your blood vessels)

You might also get this test once you’ve started treatment for one of these conditions. The sed rate can help your doctor see how well your body is responding to treatment.

You don’t need to do anything special to prepare. It’s just a basic blood test.

Let your doctor know what medicines (and supplements) you take before you have the test. Certain drugs can affect the results. Also let your doctor know if you are pregnant or are having your period.

A nurse or other health care provider will take a sample of your blood, usually from a vein in your arm. They will first tie a band around the upper part of your arm to make your vein fill with blood and swell up. Then they’ll clean the area with an antiseptic, and place a needle into your vein. Your blood will collect into a vial or tube.

The process should only take a couple of minutes. Afterward, you’ll get a piece of gauze and a bandage over the area to stop the bleeding.

You may feel a slight sting as your blood is drawn. Afterward, you may have a small bruise. You might feel dizzy and sore, and there might be some bleeding.

Your sample will go to a lab. You should have the results in 1 or 2 hours.

A lab technician will place your red blood cells into a tall, thin tube and check how far they fall in 1 hour. When you have inflammation in your body, abnormal proteins in your blood make red blood cells form into clumps. These clumps are heavy, so they fall to the bottom of the tube more quickly than single blood cells.

The faster the blood cells sink, the more inflammation you have in your body.

The sed rate test reports in millimeters (mm) the distance between the clear liquid (plasma) at the top of the tube and your red blood cells after 1 hour. The normal range is:

• 0 to 15 mm/hour in men younger than 50
• 0 to 20 mm/hour in men older than 50
• 0 to 20 mm/hour in women younger than 50
• 0 to 30 mm/hour for women older than 50

A high sed rate is a sign you have a disease that causes inflammation in your body.

Some conditions and medicines can affect the speed at which red blood cells fall, and they may affect your test results. These include:

• Anemia
• Older age
• Kidney problems
• Thyroid disease
• Pregnancy or having your period
• Obesity
• Drugs like birth control pills, methyldopa (Aldomet), theophylline (Theo-24, Theolair, Elixophylline), vitamin A, cortisone, and quinine

The sed rate test can only tell your doctor that you have inflammation somewhere in your body. It can’t show where the inflammation is or what caused it. Your doctor may also test for your erythrocyte sedimentation rate (ESR) or C-reactive protein (CRP) to help make a diagnosis. Both are acute phase reactants or inflammatory markers which can help point to a diagnosis or help follow treatment in a diagnosis. You will still need imaging or even biopsyies to make a specific diagnosis.

Talk to your doctor about the results of your sed rate test, and any other tests you have. Make sure you understand what the results mean, and how they’ll affect your treatment.

Top Picks

ESR Information | Mount Sinai

Erythrocyte sedimentation rate; Sed rate; Sedimentation rate

ESR stands for erythrocyte sedimentation rate. It is commonly called a “sed rate.”

It is a test that indirectly measures the level of certain proteins in the blood. This measurement correlates with the amount of inflammation in the body.

Blood is drawn from a vein (venipuncture), usually from the inside of the elbow or the back of the hand. A needle is inserted into the vein, and the blood is collected in an air-tight vial or a syringe. Preparation may vary depending on the specific test.

How the Test is Performed

A blood sample is needed. Most of the time, blood is drawn from a vein located on the inside of the elbow or the back of the hand. The blood sample is sent to a lab.

The test measures how fast red blood cells (called erythrocytes) fall to the bottom of a tall, thin tube.

How to Prepare for the Test

There are no special steps needed to prepare for this test.

How the Test will Feel

You may feel slight pain or a sting when the needle is inserted. You may also feel some throbbing at the site after the blood is drawn.

Why the Test is Performed

Reasons why a “sed rate” may be done include:

• Unexplained fevers
• Certain types of joint pain or arthritis
• Muscle symptoms
• Headache
• Other vague symptoms that cannot be explained

This test may also be used to monitor whether an illness is responding to treatment.

This test can be used to monitor inflammatory diseases or cancer. It is not used to diagnose a specific disorder.

However, the test is useful for detecting and monitoring:

• Autoimmune disorders
• Bone infections
• Certain forms of arthritis
• Inflammatory diseases

Normal Results

For adults (Westergren method):

• Men under 50 years old: less than 15 mm/hr
• Men over 50 years old: less than 20 mm/hr
• Women under 50 years old: less than 20 mm/hr
• Women over 50 years old: less than 30 mm/hr

For children (Westergren method):

• Newborn: 0 to 2 mm/hr
• Newborn to puberty: 3 to 13 mm/hr

Note: mm/hr = millimeters per hour

Normal value ranges may vary slightly among different laboratories. Talk to your health care provider about the meaning of your specific test results.

What Abnormal Results Mean

An abnormal ESR may help with a diagnosis, but it does not prove that you have a certain condition. Other tests are almost always needed.

An increased ESR rate may occur in people with:

• Anemia
• Cancers such as lymphoma or multiple myeloma
• Kidney disease
• Pregnancy
• Thyroid disease

The immune system helps protect the body against harmful substances. An autoimmune disorder is when the immune system mistakenly attacks and destroys healthy body tissue. ESR is often higher than normal in people with an autoimmune disorder.

Common autoimmune disorders include:

• Lupus
• Polymyalgia rheumatica
• Rheumatoid arthritis in adults or children

Very high ESR levels occur with less common autoimmune or other disorders, including:

• Allergic vasculitis
• Giant cell arteritis
• Hyperfibrinogenemia (increased fibrinogen levels in the blood)  
• Macroglobulinemia – primary
• Necrotizing vasculitis

An increased ESR rate may be due to some infections, including:

• Bodywide (systemic) infection
• Bone infections
• Infection of the heart or heart valves
• Rheumatic fever
• Severe skin infections, such as erysipelas
• Tuberculosis

Lower-than-normal levels occur with:

• Congestive heart failure
• Hyperviscosity
• Hypofibrinogenemia (decreased fibrinogen levels)
• Leukemia 
• Low plasma protein (due to liver or kidney disease)
• Polycythemia
• Sickle cell anemia

Pisetsky DS.