Summary

• Inflammation is part of your immune system’s response to injury and infection.
• However, it can also be a sign that you have a health problem.
• The ESR test can indicate if there is inflammation somewhere in your body. However, it cannot show where it is or what is causing it.
• The ESR test is usually ordered along with another test for inflammation, C-reactive protein.
• ESR is most useful when repeated over time to show whether inflammation is reducing or increasing.

What is ESR?

The ESR test is an easy, inexpensive, non-specific test that has been used for many years to help diagnose conditions associated with inflammation, including infections, cancers and autoimmune diseases. The ESR is said to be non-specific because it cannot show exactly where the inflammation is in your body or what is causing it. Also, ESR results can be affected by many other health conditions besides inflammation.

For this reason, the ESR is typically used together with another test for inflammation, C-reactive protein (CRP). ESR is not as accurate as the CRP test in most situations. However, because ESR is an easily performed test and requires only relatively simple equipment, many doctors still use it as an initial test when they think a patient may have inflammation.

ESR and CRP tests can show if there is inflammation and how severe it is, but they are not specific enough to diagnose a particular health condition on their own. Rather, they can give your doctor evidence that further testing may be needed. Over time, repeat testing can also be useful in assessing the effectiveness of treatments for inflammation.

Both CRP and ESR give similar information. However, CRP levels change more quickly than ESR. Your CRP level may fall to normal if your treatment has been successfully, but your ESR might still be abnormal for a while longer.

Another test that can be used along with ESR and CRP is procalcitonin (PCT). PCT plays a crucial role in distinguishing bacterial infections from viral ones. Unlike CRP or ESR, which broadly indicate inflammation, PCT is more specific to bacterial infections, making it valuable in guiding antibiotic therapy. A rising PCT level often signals a serious bacterial infection, whereas persistently low levels suggest a viral cause or non-infectious inflammation

Why get tested?

Inflammation is a vital part of your immune system’s response to injury and infection. It helps start the healing process by increasing blood flow to the affected area. This causes redness, warmth and swelling.

Inflammation can be a sign that you have a health problem somewhere in your body, and it occurs in many different illnesses. Tests for inflammation are among some of those most often used in medical care.

Acute and chronic inflammation

There are two types of inflammation: acute and chronic. In acute inflammation, such as when you have an injury or an infection from a virus or bacteria, your immune system sends out chemical messengers and releases white blood cells to protect the affected area. When the wound or infection has cleared up, your body goes back to normal. In chronic inflammation, your immune system keeps sending out chemical messengers and white blood cells over a long time and in some situations can start attacking nearby healthy tissues and organs.

How is an ESR performed?

The ESR test measures how fast red blood cells settle to the bottom of a tall tube of blood. Inflammation causes red blood cells to stick together and form clumps. Being heavier, the clumps fall to the bottom of the tube faster than other red blood cells.

Results are reported as how many millimetres of clear plasma are present at the top of the column after one hour. Normally, red cells fall slowly, leaving little clear plasma.

Having the test

Sample

Blood

Preparation

None

Your results

Reading your test report

Your results will be presented along with those of your other tests on the same form. You will see separate columns or lines for each of these tests.

Reference intervals
Your results will be compared to reference intervals (sometimes called a normal range).

• Reference intervals are the range of results expected in healthy people.
• When compared against them your results may be flagged high or low if they sit outside this range.
• Many reference intervals vary between labs so only those that are standardised or harmonised across most laboratories are given on this website.

If your results are flagged as high or low this does not necessarily mean that anything is wrong. It depends on your personal situation. Your results need to be interpreted by your doctor.

Specific reference intervals for ESR based on age and sex.

• Newborns (0-31 days): 0-4 mm/hr
• Infants (31-91 days): 0-9 mm/hr
• Children (91 days - 12 years): 0-14 mm/hr
• Men (12-65 years): 1-15 mm/hr
• Men (more than 65 years): 1-30 mm/hr
• Women (12-18 years): 1-15 mm/hr
• Women (18-65 years): 1-20 mm/hr
• Women (more than 65 years): 1-35 mm/hr

These values may vary slightly depending on laboratory methodology and patient-specific factors.

More to know?

Your doctors may request a group of tests together, including CRP, ESR, Liver Function Tests and a Full Blood Count among others. Tests specific to your symptoms may also be ordered such as the ANA (antinuclear antibody) and RF (rheumatoid factor) for autoimmune diseases. If it’s possible you have an infection, cultures will sometimes be ordered to identify the type of bacteria.

Females tend to have a slightly higher ESR, and menstruation and pregnancy can cause temporary elevations.

Drugs such as dextran, methyldopa (Aldomet), oral contraceptives, penicillamine procainamide, theophylline and vitamin A can increase ESR, while aspirin, steroids and quinine may decrease it.

The ESR is helpful in diagnosing two specific inflammatory diseases, temporal arteritis and polymyalgia rheumatica. A high ESR is one of the main test results used to confirm the diagnosis. It is also used to monitor disease activity and response to therapy in both of these diseases.

Questions to ask your doctor

The choice of tests your doctor makes will be based on your medical history and symptoms. It is important that you tell them everything you think might help.

You play a central role in making sure your test results are accurate. Do everything you can to make sure the information you provide is correct and follow instructions closely.

Talk to your doctor about any medications you are taking. Find out if you need to fast or stop any particular foods or supplements. These may affect your results. Ask:

• Why does this test need to be done?
• Do I need to prepare (such as fast or avoid medications) for the sample collection?
• Will an abnormal result mean I need further tests?
• How could it change the course of my care?
• What will happen next, after the test?

More information

Pathology and diagnostic imaging reports can be added to your My Health Record. You and your healthcare provider can now access your results whenever and wherever needed.

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