C-Reactive Protein (CRP) Test

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What It Means to Have High C-Reactive Protein Levels

Richard N. Fogoros, MD, is a retired professor of medicine and board-certified in internal medicine, clinical cardiology, and clinical electrophysiology.

Updated on October 07, 2022

Chris Vincent, MD, is a licensed physician, surgeon, and board-certified doctor of family medicine.

Table of Contents
Table of Contents

When c-reactive protein (CRP) is high, it’s a sign of inflammation in the body. What constitutes a “high” level varies from person to person, but a reading of 2 milligrams per liter or above is often considered a dangerous CRP level and puts you at risk for a heart attack.

One of the most important and most popular changes to the health insurance landscape brought about by the passing of the Affordable Care Act was the prohibition against denying patients health insurance, or charging them more, if they had preexisting conditions. Research shows that 27% of Americans in the 18 to 64 age group have what would have been considered a “declinable medical condition” before the Affordable Care Act took effect, and in some regions, the percentage of patients with preexisting conditions rises to nearly four in 10, the Henry J. Kaiser Family Foundation

In addition to being associated with coronary artery disease (CAD), CRP is also related to complications from COVID-19, arthritis, and other conditions.

This article explains what it means for your c-reactive protein to be elevated. It explains CRP blood tests, possible causes for high CRP levels, and the medication and lifestyle changes that may be used to treat it.

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CRP Blood Tests

Healthcare providers don’t routinely test CRP like they do other things. Most experts do not recommend doing so, including the United States Preventive Services Task Force.

You may have your CRP levels checked if your healthcare provider thinks you could have an infection or another inflammation-causing condition. And if you don’t have any obvious symptoms, a high CRP level might take you by surprise.

The CRP produced in the liver is a response to the activity of white blood cells that fight infection and inflammation in the body. Their heightened activity causes more CRP to be made, making it a biomarker for inflammation that can be detected by a blood test.

In most healthy adults, the c-reactive protein normal range is 0.3 milligrams per deciliter (mg/dL) or less, but with autoimmune conditions such as lupus and rheumatoid arthritis, that may be the case even if inflammation is present. Other values include:

Between 0.3 mg/dL and 1.0 mg/dL, considered mildly elevated
Between 1 mg/dL and 10 mg/dL, considered moderately elevated
Above 10 mg/dL, considered to be highly elevated

The hs-CRP Test

A high-sensitivity CRP (hs-CRP) test is a slightly different blood test. It measures very low amounts of CRP, with a focus on cardiac risk and prevention of heart-related disease. The American College of Cardiology and American Heart Association consider a level of 2 mg/L and above to be a possible risk factor for heart attacks.

What Elevated CRP Levels Mean

When CRP levels remain elevated for a long time, it can indicate chronic inflammation of the blood vessels. This type of low-grade inflammation contributes to the deposit of fat and other substances in the artery walls, a condition called atherosclerosis.

This build-up can narrow the arteries that feed the heart blood, causing coronary artery disease (CAD). Over time, heart attack, stroke, or heart failure can occur. This is true even for those with elevated CRP levels who have no obvious symptoms or signs of active inflammation.

Inflammation is an important contributor to atherosclerosis and elevated CRP is associated with an increased risk of CAD. A study of 376 people found that 210 of them diagnosed with CAD all had elevated CRP levels when compared with 166 people who did not have CAD.

The CRP level increased in step with the degree of blood vessel damage evaluated by coronary angiography, an imaging test used to visualize blood flow through the heart.

What CRP Level Is Dangerously High?

Whether a CRP level is dangerous will depend on the type of c-reactive protein test used, your individual medical history, and the suspected cause of inflammation. Your healthcare provider can best explain the test results to you. In general, anything above 1 mg/dL is elevated and may require intervention. The higher the level, the more likely you will need a diagnosis and treatment for its cause.

Addressing Your Risk Factors

A number of risk factors may contribute to CRP levels, and there may be benefits to taking steps to reduce your CRP levels. Treatment aimed at lowering CRP levels may reduce cardiovascular risk, but researchers are still working to understand these relationships.

C-Reactive Protein Treatment

While it is still uncertain how important it is to reduce elevated CRP, experts have identified several ways of doing so.

Lifestyle Changes

You don’t necessarily need medicine to lower your levels of CRP. Taking steps to make your lifestyle healthier can also help.

Ways to reduce your CRP without drugs include:

Increasing your aerobic exercise (e.g, running, fast walking, cycling)
Quitting smoking
Losing weight
Eating a heart-healthy diet

Some of these strategies can also reduce certain heart disease risk factors, such as obesity and high blood pressure. You also may wish to reduce stress and anxiety. Some studies have found higher CRP levels in males with anxiety disorder, although it’s not clear that anxiety causes high CRP levels.

Statins

Statins are drugs that lower cholesterol. Studies have shown that they can reduce CRP levels by 13% to 50%.

Statins can also substantially reduce the risk of heart attack and stroke in even healthy-appearing patients whose CRP levels are high.

Statins shown to bring down CRP levels and reduce related cardiac risks include:

Crestor (rosuvastatin)
Lipitor (atorvastatin)
Mevacor (lovastatin)
Pravachol (pravastatin)
Zocor (simvastatin)

If you have high CRP levels, especially if you have one or more additional risk factors for heart disease, you should discuss the option of taking a statin drug with your healthcare provider.

Does Aspirin Help?

Aspirin does not specifically reduce levels of CRP. However, daily aspirin therapy can be used as a heart attack and stroke prevention measure, but the risks of taking aspirin for prevention may outweigh the benefits.

Those with elevated CRP may benefit from aspirin therapy more than people whose CRP levels are normal. It may be recommended for some people with elevated CRP who are at a higher risk of heart disease or who have already experienced one of these consequences.

Aspirin therapy isn’t for everyone. Always talk to your healthcare provider before taking low-dose aspirin for daily therapy.

You can lower your CRP levels by adopting a healthy lifestyle and, if appropriate, taking a statin. These strategies can help lower your CRP levels and potentially reduce your cardiovascular risk.

Summary

Elevated CRP levels indicate there is inflammation in the body.

Inflammation cannot only be an indicator of issues like an infection or arthritis, but a contributing factor for heart concerns like hardening of the arteries.

It remains unknown whether CRP itself increases cardiovascular risk. It could be that it merely reflects the vascular injury and inflammation that results from other risk factors.

Regardless, elevated CRP must be taken seriously as it is associated with conditions that affect the health of your heart and the supply of blood to the rest of your body.

Frequently Asked Questions

Is CRP Related to COVID?

High c-reactive protein (CRP) is a sign of inflammation in the body, which puts you at risk for a number of disorders. High CRP in COVID-19 is associated with complications of the coronavirus, including venous thromboembolism, acute kidney injury, critical illness, and mortality.

Is there a natural way to lower CRP?

Statins are the usual course of treatment for high CRP levels. However, diet and exercise may also lower your levels. Choose anti-inflammatory foods such as salmon, tuna, and plant-based proteins. Avoid processed meat, consume omega-3 fatty acids or monounsaturated fatty acids, and include more fresh fruits and vegetables.

What cancers have high CRP?

Several types of cancer are among the diseases that can cause c-reactive protein to be elevated. Studies have demonstrated an association between high CRP levels and cancers of the liver, lung, colon, breast, and endometrium.

11 Sources

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

Arnett DK, Blumenthal RS, Albert MA, et al. 2019 ACC/AHA Guideline on the primary prevention of cardiovascular disease: Executive summary: A report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. Circulation. 2019;140(11):e563-e595. doi:10.1161/CIR.0000000000000677
U.S. Preventive Task Force. Cardiovascular disease: Risk assessment with nontraditional risk factors.
Icahn School of Medicine at Mount Sinai. C-reactive protein.
Kishimoto Y, Aoyama M, Saita E, Ohmori R, Tanimoto K, Kondo K, et al. No Significant Association Between Plasma Endosialin Levels and the Presence or Severity of Coronary Artery Disease. J Clin Med Res. 2022 May;14(5):202-208. doi:10.14740/jocmr4730.
Alfaddagh A, Martin SS, Leucker TM, Michos ED, Blaha MJ, Lowenstein CJ, et al. Inflammation and cardiovascular disease: From mechanisms to therapeutics. Am J Prev Cardiol. 2020 Nov 21;4:100130. doi:10.1016/j.ajpc.2020.100130
Vogelzangs N, Beekman AT, de Jonge P, Penninx BW. Anxiety disorders and inflammation in a large adult cohort. Transl Psychiatry. 2013 Apr 23;3(4):e249. doi:10.1038/tp.2013.27.
Calza L, Trapani F, Bartoletti M, et al. Statin therapy decreases serum levels of high-sensitivity C-reactive protein and tumor necrosis factor-α in HIV-infected patients treated with ritonavir-boosted protease inhibitors. HIV Clin Trials. 2012;13(3):153-61. doi:10.1310/hct1303-153
American Heart Association. Aspirin and heart disease.
Smilowitz NR, Kunichoff D, Garshick M, et al. C-reactive protein and clinical outcomes in patients with COVID-19. European Heart Journal. 2021;42(23):2270-2279. doi:10.1093/eurheartj/ehaa1103
Texas Heart Institute. How can one naturally lower an elevated CRP count?
Li J, Jiao X, Yuan Z, Qiu H, Guo R. C-reactive protein and risk of ovarian cancer: A systematic review and meta-analysis. Medicine. 2017;96(34):e7822. doi:10.1097/md.0000000000007822

Additional Reading

U.S. Preventive Services Task Force, Curry SJ, Krist AH, et al. Risk Assessment for Cardiovascular Disease With Nontraditional Risk Factors: US Preventive Services Task Force Recommendation Statement. JAMA 2018; 320:272.

By Richard N. Fogoros, MD
Richard N. Fogoros, MD, is a retired professor of medicine and board-certified in internal medicine, clinical cardiology, and clinical electrophysiology.

C-Reactive Protein (CRP) Test

A C-reactive protein (CRP) test measures the level of C-reactive protein in your blood. Your liver releases CRP into your bloodstream in response to inflammation. Healthcare providers use this test to help diagnose and monitor several different causes of inflammation, such as infections and certain autoimmune conditions.

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Overview

What is a C-reactive protein (CRP) test?

A C-reactive protein (CRP) test measures the level of C-reactive protein — a protein made by your liver — in your blood. Your liver releases CRP into your bloodstream in response to inflammation.

When your body encounters an offending agent (like viruses, bacteria or toxic chemicals) or you have an injury, it activates your immune system. Your immune system sends out its first responders: inflammatory cells and cytokines.

These cells begin an inflammatory response to trap bacteria and other offending agents or start healing injured tissue. The result can be pain, swelling, bruising or redness. But inflammation also affects body systems you can’t see, such as your joints.

You normally have low levels of CRP in your blood. Moderately to severely elevated levels may be a sign of a serious infection or other inflammatory condition.

Why do healthcare providers perform CRP tests?

Healthcare providers typically order a C-reactive protein (CRP) test to help diagnose or rule out certain conditions, including:

Severe bacterial infections, such as sepsis.
Fungal infections.
Osteomyelitis (infection of your bone).
Inflammatory bowel disease (IBD).
Some forms of arthritis.
Autoimmune diseases, such as rheumatoid arthritis or lupus (systemic lupus erythematosus).
Pelvic inflammatory disease (PID).

Providers also use CRP tests to monitor people after surgery or other invasive procedures to check for infection during their recovery period.

A CRP test alone can’t diagnose a condition or where the inflammation is in your body. Because of this, providers generally order additional tests if the CRP results show that you have inflammation.

When would I need a C-reactive protein (CRP) test?

Your healthcare provider may order a CRP test if you have symptoms of a serious bacterial infection, including:

Fever.
Chills.
Rapid breathing (tachypnea).
Rapid heart rate (tachycardia).
Nausea and vomiting.

Your provider may also use CRP tests to monitor your treatment if you’ve already been diagnosed with an infection or a chronic inflammatory condition.

CRP levels increase and decrease depending on how much inflammation your body has. If your CRP levels go down, it’s a sign that your treatment for the inflammation is working.

Test Details

Who performs a CRP test?

A healthcare provider called a phlebotomist usually performs blood draws, but any healthcare provider who is trained in drawing blood can perform this task. The samples are sent to a lab where a medical laboratory scientist prepares the samples and performs the test on machines known as analyzers.

How do I prepare for a C-reactive protein (CRP) test?

Your healthcare provider will let you know what you need to do to prepare for a CRP test, but in most cases, you won’t need to do anything special to prepare for it (such as fasting before the test).

What should I expect during my CRP test?

You can expect to experience the following during a blood test, or blood draw:

You’ll sit in a chair, and a healthcare provider will check your arms for an easily accessible vein. This is usually in the inner part of your arm on the other side of your elbow.
Once they’ve located a vein, they’ll clean and disinfect the area.
They’ll then insert a small needle into your vein to take a blood sample. This may feel like a small pinch.
After they insert the needle, a small amount of blood will collect in a test tube.
Once they have enough blood to test, they’ll remove the needle and hold a cotton ball or gauze on the site to stop the bleeding.
They’ll place a bandage over the site, and you’ll be finished.

What should I expect after my CRP test?

After a healthcare provider has collected your blood sample, they’ll send it to a laboratory for testing. Once the test results are back, your healthcare provider will share the results with you.

What are the risks of a C-reactive protein (CRP) test?

Blood tests are a very common and essential part of medical testing and screening. There’s very little risk to having blood tests. You may have slight tenderness or a bruise at the site of the blood draw, but this usually resolves quickly.

Results and Follow-Up

When should I know the results of my C-reactive protein (CRP) test?

In most cases, you should have your CRP test results within one or two days, though it could take longer.

What type of results do you get for a C-reactive protein (CRP) test?

Blood test reports, including CRP blood test reports, usually provide the following information:

The name of the blood test or what was measured in your blood.
The number or measurement of your blood test result.
The normal measurement range for that test.
Information that indicates if your result is normal or abnormal or high or low.

What is the normal range for a CRP test?

Laboratories have different reference ranges for normal C-reactive protein (CRP) levels. When you get your blood test results back, there will be information that indicates what that lab’s normal CRP range is.

In general, the normal CRP level is less than 0.9 milligrams per deciliter (mg/dL).

Many factors can affect your CRP level. Minor CRP level elevation may be due to the following conditions or situations:

People assigned female at birth and elderly people have naturally higher levels of CRP.

If you have any questions about your results, be sure to ask your healthcare provider.

What does a high CRP level mean?

If you have a moderately to severely elevated CRP level, it probably means you have some type of inflammation. But a CRP test can’t show the cause of the inflammation or where it is in your body. Because of this, your healthcare provider will likely order additional tests if your result shows a high CRP level.

How high your CRP level is can mean different things.

Moderate elevation

A CRP test result of 1.0 to 10.0 milligrams per deciliter (mg/dL) is generally considered a moderately elevated level. This result may indicate any of the following conditions:

Systemic inflammation from conditions such as rheumatoid arthritis (RA), systemic lupus erythematosus (SLE) or other autoimmune conditions.
Heart attack (myocardial infarction).
Pancreatitis.
Bronchitis.

Marked elevation

A CRP test result of more than 10 mg/dL is generally considered a marked elevation. This result may indicate any of the following conditions:

Acute bacterial infections.
Viral infections.
Systemic vasculitis.
Major injury (trauma).

Severe elevation

A CRP test result of more than 50 mg/dL is generally considered severe elevation. Results over 50 mg/L are associated with acute bacterial infections about 90% of the time.

What does a low CRP level mean?

Since the normal CRP level is generally less than 0.9 mg/dL, there’s no such thing as a lower than normal CRP level.

If you previously had a high CRP result and now have a lower result, it likely means your inflammation is decreasing and/or your treatment for the inflammation is working.

Should I be concerned if my CRP level is abnormal?

If your CRP test results reveal that you have high levels of CRP, it doesn’t necessarily mean that you have a medical condition that needs treatment, especially if they’re only slightly elevated. Several factors, such as smoking, recent injury and certain health conditions, can raise your CRP levels. There could’ve also been an error in the collection, transport or processing of the test.

If you have an abnormal result, your healthcare provider will discuss your results with you. They may order additional tests to determine the cause of your abnormal CRP levels.

A note from Cleveland Clinic

Seeing an abnormal test result can be stressful. Know that having an elevated CRP level doesn’t necessarily mean you have a medical condition and need treatment. Approximately 1 in 20 healthy people will have results outside of the normal range. Your healthcare provider will let you know if you need to have further tests to determine the cause of the abnormal level. Don’t be afraid to ask your provider questions. They’re available to help you.

C-Reactive Protein (CRP) Test

What It Means to Have High C-Reactive Protein Levels