ESR Test: Why Your Doctor Checks Your Sedimentation Rate

An ESR test is one of the most common blood tests ordered by doctors. Many patients are confused as to what this test measures and why their doctor orders it.

An ESR test is used to determine if there is inflammation in the body. Like other lab tests, the results are interpreted within a defined range. Each lab interprets ESR test results differently. Results are reported in millimeters/hour (mm/hr).

This article will help provide a better understanding of the ESR test, ESR test ranges, normal ESR ranges, and why your doctor orders this test.

What Is the Meaning of the ESR Test?

Let's start with the basics. ESR stands for Erythrocyte Sedimentation Rate. It's also called the sedimentation rate test, or simply "sed rate."

ESR Test Meaning in Simple Words

The term Erythrocyte Sedimentation Rate (ESR) refers to the rate at which the red blood cells settle to the bottom of the test tube over a period of 1 hour. The test is also called the Sedimentation Rate Test or Sed Rate. In essence, they all mean the same thing.

Why Is It Called the Sedimentation Rate Test?

The word "sedimentation" simply means settling. So the sedimentation rate test is just another name for the ESR test. Both terms are used interchangeably by doctors and labs.

If red blood cells settle quickly, that can indicate inflammation in the body. When there is inflammation, certain blood proteins increase and cause red blood cells to stick to each other. Clumped cells are heavier than normal cells and thus fall faster.

Why Your Doctor Orders an ESR Test

Your doctor is unlikely to order an ESR test without some reason to do so.

Symptoms That Lead to an ESR Test

Your doctor may suggest an ESR test if you have:

• A fever lasting longer than a few days, for which no cause has been found,
• Stiffness and/or pain in the joints, particularly if it occurs in the morning and/or is in several joints,

• Fatigue that is unrelenting and for which no cause can be found,

• Loss of appetite and/or weight for which no cause can be found,

• Aches in the muscles of the shoulders or hips,

• Headaches that are persistent and/or are with tenderness in the scalp,

None of these symptoms, in and of themselves, can be cause for a medical diagnosis. Because of this, an ESR test can be useful because it is one more piece to the diagnostic puzzle.

Conditions Monitored With an ESR Test

An ESR test can also be done to see how a treatment is working. This is common with conditions that are long-term and/or chronic, such as:

• Rheumatoid arthritis
• Lupus
• Inflammatory bowel disease
• Polymyalgia rheumatica
• Giant cell arteritis
• Chronic infections

If, after treatment for any of these is begun, an ESR test shows a decrease in the result, it can be an indicator that the treatment is working. An increase may mean the treatment needs to be changed.

How the ESR Test Works

The actual ESR test is not complicated and is done in only a few minutes.

ESR Test Procedure Step by Step

Steps in performing an ESR test

1. Blood is drawn from the arm in the same way as a routine blood test.

2. The blood is placed in a tube, which is then stood up vertically.

3. The tube is left standing for a period of 1 hour.

4. During this time, the heavier red blood cells settle to the bottom of the tube.

5. The distance that the cells have settled is then measured by a technician in millimeters.

That measurement becomes your ESR test result.

How to Prepare for an ESR Test

Good news — there's almost no preparation needed for an ESR test. You usually don't need to fast. You can eat and drink normally before the test.

However, it helps to tell your doctor about:

• Any medications you're currently taking
• Pregnancy, if applicable
• Recent infections or illnesses

These factors can affect your ESR test range, so your doctor needs the full picture before interpreting results.

ESR Test Normal Range

ESR ranges can vary from lab to lab. However, normal ranges are typically defined as:

ESR Normal Range by Age and Gender

The ESR normal range varies slightly between labs, but general guidelines are:

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

Women typically show a slightly higher ESR normal range than men. This happens because women naturally have higher levels of certain blood proteins that affect sedimentation.

ESR Normal Range in Children

ESR, or erythrocyte sedimentation rate, is a clinical test that helps determine how quickly the red blood cells fall to the bottom of an empty tube. This test is often used to screen for inflammation and infection.

ESR normal range in children is different than adults. Generally, labs consider a healthy range for children to be between 0-10 mm/hr.

It’s important to understand that every lab has its own way of testing and reporting normal ranges. The range printed on your lab report should always be used as a reference. Normal ranges that you find online may not always be accurate.

ESR Test Range: High vs Low Results

Once you receive your test results, the most common question is, what do the numbers mean?

What a High ESR Test Range Means

ESR test results may be high for many reasons. Common reasons may include:

• Infections

• Autoimmune disorders

• Chronic diseases

• Cancers

• Pregnancy

A high result may not always mean that there is a serious health concern. Your doctor will use this information along with other tests and your symptoms to determine the cause.

What a Low ESR Test Range Means

A low ESR test range is less common but still worth noting. It may be linked to:

• Polycythemia, a condition with too many red blood cells
• Sickle cell disease
• Certain blood protein abnormalities
• Severe liver disease

As with high results, a low ESR test result is interpreted alongside your full medical picture, not as a standalone answer.

ESR Test During Pregnancy

An increase in sedimentation rate during pregnancy is to be expected.

Blood volume and protein levels increase during pregnancy, and routine lab work reflects these changes. Doctors factor these into their assessment of your tests. "High" results on tests don't necessarily mean a pregnant patient is not in the normal range.

Common Myths About ESR Test

A lot of misinformation floats around this simple blood test. Let's clear up a few common myths.

Myth 1: A high result means cancer. Many benign conditions, including a cold or flu, infection, or even a sprained joint, can cause results to be slightly elevated. A high result does not mean that cancer is definitely present.

Myth 2: This test will tell you if you have arthritis. ESR can tell you if you have inflammation, but to confirm if you have arthritis, your doctor will perform a physical exam, review your history, order X-rays or other imaging studies, or order other blood tests.

Myth 3: You have to fast before this test. There is no need to fast before taking this test.

Myth 4: One abnormal result means something is permanently wrong. A single value is not an endpoint. Usually, your doctor will need to monitor your condition and repeat the test several times to see if there is actual improvement.

Who Should Get an ESR Test Regularly?

There are some conditions where routine testing is required, for example:

People with diagnosed autoimmune conditions. If you are diagnosed with lupus or RA, your doctor may want to test you regularly to see how the condition is impacting you.

Patients on long-term anti-inflammatory treatment. If you are taking long-term anti-inflammatory medications, your doctor may want to test you routinely to see how inflammation is being impacted.

People Ages 50 and Older with Vague Symptoms. Symptoms like fatigue, joint stiffness, and unexplained weight loss in people over the age of 50 warrant routine testing to check for conditions like polymyalgia rheumatica and giant cell arteritis, which become more prevalent at older ages.

People Recovering from a Serious Infection. Routinely checking levels a few weeks after a serious infection is to ensure the body has fully returned to baseline.

Unless your doctor indicates otherwise, you shouldn’t need routine testing.

Reading Your Report Correctly

Your lab report will show a number in mm/hr and a reference range specific to your age and gender.

Your number in relation to the reference range will indicate inflammation in the following ways:

This is a general case guide; to review your results, you should consult your doctor to see how your personal case history impacts test results.

ESR Test vs CRP Test

The ESR (erythrocyte sedimentation rate) test and the CRP (C-Reactive Protein) test are often confused with one another since they both assess inflammation.

The ESR test measures the rate at which red blood cells settle. The CRP test measures the level of a specific inflammatory protein in the blood.

Which Test Is Better?

Neither test is better in an absolute sense. They’re typically used in conjunction because:

• CRP responds faster to newly formed inflammation and falls faster once inflammation is resolved
• ESR is more useful in tracking chronic conditions because it takes weeks for it to rise and fall.

Which combination your doctor uses depends on your symptoms.

Factors That Can Affect Your Results

Many everyday factors can affect your results even when there is no disease present. Some of these factors can make your results trend higher or lower.

Age. Even in healthy people, results can trend higher with age

Anemia. In the absence of inflammation, a low red blood cell count can increase results.

Medications. Birth control pills, aspirin, and certain steroids can all increase results.

Menstrual cycle and pregnancy. Results can be elevated during these times due to hormonal shifts.

Obesity. People with a higher body fat percentage can have mildly elevated baseline inflammation, according to some studies. 

Since there are so many factors that can affect your results, your doctor takes these factors into account and doesn’t solely rely on your numbers.

Limitations of the ESR Test

The ESR test cannot name the disease causing inflammation. It cannot diagnose cancer or infection on its own. Even if you have a normal ESR test, it doesn’t necessarily rule out a medical condition. ESR test results can be shifted by age, pregnancy, anemia, and certain medications.

The reason why doctors won't base their diagnosis on a single ESR test is that it is always read in conjunction with your other symptoms, physical exam, and other lab tests.

Tips to Support Healthy Inflammation Levels

Some people think that it is difficult to “control” your inflammation level like you can with your blood sugar level. However, there are things you can do to support healthy inflammatory levels throughout your body:

• Stay hydrated. Dehydration can affect your blood test results and can cause mild inflammation throughout your body.
• Manage chronic conditions. Maintaining balance with your blood sugar, thyroid conditions, and/or arthritis can also help manage your inflammation markers.
• Avoid unnecessary self-medication. Some over-the-counter drugs can conceal or affect your body’s inflammatory levels.
• Get adequate sleep. Poor sleep is associated with elevated inflammatory levels.
• Eat an anti-inflammatory diet. Incorporate foods rich in omega-3 and consume fewer pro-inflammatory foods.

Doing the above will support your body's overall inflammatory health along with whatever your doctor prescribes.

How to Book an ESR Test

Getting an ESR test is much easier these days.

ESR Test at Home

You can collect your sample at the convenience of your own home. Several diagnostic centers allow home sample collection for an ESR test. You can book an ESR test online and choose a time slot that is convenient for you. After that, a trained person will go to your home to collect the sample. You will get your digital report within 24 hours.

This is convenient for the elderly, persons managing chronic inflammatory conditions, and those with busy schedules requiring routine monitoring of ESR.

How Much Does An ESR Test Cost?

Price varies from city to city and lab to lab, but this test is comparatively cheaper than most other blood tests.

In the range of 150 to 400 Rupees is the going rate for this test in most cities in India, with labs in metros charging on the higher side.

Most diagnostic centers have this test in their inflammation or arthritis panel and may offer it at a discounted bundle price. If you are considering multiple markers, be sure to ask the lab if bundling is available.

Home collection is offered at no extra charge by most labs, making it a value-add at no extra cost.

When Should You See a Doctor After Getting Results?

Most of the time, you don't need to see your doctor immediately after results, but if;

• Your result is way above the reference range, and you have a fever or are in pain

• There is a trend in your results showing a constant increase

• Your result is abnormal, and you have new symptoms like swelling or rash

• Your doctor told you to see them after results

Other times, your results may be reviewed by your doctor during your next routine checkup to decide if further tests are required.

Quick Takeaways

These are the main points you should remember:

• To perform an ESR test, one has to measure how quickly red blood cells settle in a certain time period, usually an hour.

• An ESR test doesn't diagnose any specific condition, but detects the presence of inflammation in the body.

• The ESR normal range depends on your age and gender.

• No special preparation or fasting is required before taking this test.

• Sampling is done at home and is easily available.

• Finding abnormal results for this test doesn't always mean you should be concerned.

You should have this information whenever your doctor is planning to order this test for you.

Frequently Asked Questions About ESR Test

1. What is ESR test used for?

An ESR test is used to detect inflammation in the body. Based on the result, doctors can either diagnose conditions like infections, arthritis, and other autoimmune disorders, or help in determining the effectiveness of the treatment prescribed to the patient.

2. How much does an ESR test cost?

The cost of an ESR test is between 150- 400 INR, depending on the lab and city. It is usually more affordable to get this test done at larger diagnostics centers.

3. Can I get an ESR test done at home?

Yes. All major diagnostics labs offer home sample collection for the ESR test, and the cost is the same as that of collection done at their center. You can book an appointment online, and a phlebotomist will be sent to your home to collect the sample.

4. Do I need to fast before an ESR test?

No, it isn’t necessary to fast before an ESR test. In fact, you’re allowed to eat and drink before the test, unless your doctor also ordered a different test that requires you to fast.

5. How long does it take to get ESR test results?

Most labs will give you the results of your ESR test within 24 hours of collecting the sample. However, if your lab is pretty busy that day, you may have to wait a bit longer to get your results.

6. Is a high ESR test range always serious?

Not always. An elevated ESR range usually only tells your doctor that there is inflammation. This could be caused by a multitude of reasons. A less serious reason could be a minor infection or even pregnancy.

7. What is the difference between ESR test and CBC test?

A CBC (or complete blood count) gives your doctor information about the amount and health of different kinds of blood cells. An ESR test measures how long it takes for red blood cells to settle, indicating inflammation.

8. How often should I repeat an ESR test if I have a chronic condition?

Again, this is up to your doctor’s discretion and depends on your specific chronic condition. Patients with chronic inflammatory conditions, like rheumatoid arthritis, are often assessed through ESR tests to see how effective their treatment is.

Related Blood Tests Worth Knowing About

ESR tests are often ordered with other basic blood tests to give your doctor a fuller picture of your health.

If you're new to blood testing in general, it's worth reading our guide on the CBC test and what its results mean, since a Complete Blood Count is almost always checked together with inflammation markers like ESR.

For a deeper clinical reference on sedimentation rate testing, patients can also review the detailed explanation published by the Cleveland Clinic on sed rate testing, which covers how healthcare providers use this marker across different specialties.

Reading around a single report helps you ask better questions at your next appointment, rather than guessing at what each line means on your own.

Final Thoughts on ESR Test

In terms of the ESR test, it is an affordable, simple blood test that can alert your doctor to potential inflammation in the body. On its own, it will not name a specific disease process, but it can aid your doctor in their diagnosis along with other test results and your history of signs and symptoms.