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:
- 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.
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.
The entire procedure usually takes less than five minutes.
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:
- Cigarette smoking.
- Common cold.
- Recent injury.
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.
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).
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).
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.
What is the purpose of CRP test? ›
Your health care provider might order a C-reactive protein test to: Check for infection. Help diagnose a chronic inflammatory disease, such as rheumatoid arthritis or lupus. Learn your risk of heart disease.What does it mean if your C-reactive protein is high? ›
A high level of CRP in the blood can be a marker of inflammation. A wide variety of conditions can cause it, from an infection to cancer. High CRP levels can also indicate that there's inflammation in the arteries of the heart, which can mean a higher risk of heart attack.What is the most common cause of high CRP? ›
The most common cause of high CRP levels is a severe infection. Other possible causes include a poorly controlled autoimmune disease and severe tissue damage. Read on to learn more about CRP levels, including how doctors check these levels, the normal ranges, and what can cause elevated levels in the body.What is a normal CRP level? ›
Interpretation of CRP levels:
Less than 0.3 mg/dL: Normal (level seen in most healthy adults). 0.3 to 1.0 mg/dL: Normal or minor elevation (can be seen in obesity, pregnancy, depression, diabetes, common cold, gingivitis, periodontitis, sedentary lifestyle, cigarette smoking, and genetic polymorphisms).
Angiotensin receptor blockers (ARBs) (valsartan, irbesartan, olmesartan, telmisartan) markedly reduce serum levels of CRP. The findings with other ARBs (losartan and candesartan) were inconsistent. Antidiabetic agents (rosiglitazone and pioglitazone) reduce CRP levels, while insulin is ineffective.Is high CRP life threatening? ›
Or it may be a potentially life-threatening condition called sepsis or blood poisoning. Symptoms of sepsis may include fever and chills, headache, pain, nausea, vomiting, confusion, rash, and shortness of breath. The level of CRP in your blood goes up within a few hours of a serious infection.Does high C-reactive protein mean arthritis? ›
Drawbacks of CRP tests
This is because CRP is not specific to RA. Elevated levels of CRP can indicate any infection or inflammatory condition. On the other hand, some people with RA may have normal CRP levels.
Third, CRP is only one of the inflammatory markers, and a recent study has reported that genetically predicted circulating concentrations of several inflammatory-related cytokines were associated with the risk of breast, endometrial, lung, ovarian, and prostate cancer .What foods should I avoid if my CRP is high? ›
For example, ultra-processed foods like fast food, frozen meals, and processed meats have been associated with higher blood levels of inflammatory markers like CRP ( 90 , 91 , 92 ).What is the main cause of inflammation in the body? ›
The most common reasons for chronic inflammation include: Autoimmune disorders, such as lupus, where your body attacks healthy tissue. Exposure to toxins, like pollution or industrial chemicals. Untreated acute inflammation, such as from an infection or injury.
Can stress cause high CRP levels? ›
CRP is elevated in chronic stress and may be the link between stress and low-grade inflammation-related diseases. Scientists found that both psychological and social stress significantly impacts CRP .What happens if high CRP is left untreated? ›
Even if you have no symptoms of disease, elevated CRP signals increased risk for cardiovascular disease, cancer, diabetes, obesity, and more. Additionally, there's strong evidence that people with lower CRP levels have fewer inflammation-related diseases.Can high CRP be cured? ›
There's no doubt that the very best way to lower CRP is through exercise, weight loss, and dietary control; of course, those are all proven already to lower vascular risk.How long does it take for CRP to return to normal? ›
CRP shows a rapid response to infection and inflammation, increasing within hours of stimulus and returning rapidly to normal following resolution. Typically CRP begins to rise within 4-6 hours of stimulus, peaks within 36–50 hours, and returns to normal 3–7 days following resolution.What does it mean when your blood test shows inflammation? ›
Blood tests known as 'inflammatory markers' can detect inflammation in the body, caused by many diseases including infections, auto-immune conditions and cancers. The tests don't identify what's causing the inflammation: it might be as simple as a viral infection, or as serious as cancer.How long does it take to reduce CRP? ›
This corresponds to a negative predictive value with respect to further treatment of 99% (95% confidence interval, 95.4% to 99.9%). The mean treatment duration was 3.7 (median, 4; range, 3 to 6) days in the CRP-guided group and 5.5 (median, 5; range, 5 to 7) days in the at least 5-day study group.What doctor treats high CRP? ›
In addition to blood tests that measure inflammation, such as the CRP test, and antibodies, rheumatologists look at factors like physical symptoms and imaging, such as X-rays and MRIs.Which fruits reduce CRP level? ›
Cherries. Cherries and other berries contain substances called antioxidants that help to calm inflammation. When people in one study ate 45 Bing cherries every day for about a month, their levels of CRP fell by 20%.Can high blood pressure cause high CRP? ›
Discussion. In the present study, hypertension was associated with higher CRP levels in both men and women. Systolic BP and pulse pressure, but not diastolic BP, were associated with CRP.Can CRP be high without infection? ›
It is important to note that several conditions can be associated with marked elevations of CRP levels, with infection being most common (particularly at extreme elevations). We could not distinguish between conditions based on the CRP level, but above 350 mg/L the cause was almost always infection.
What level of CRP indicates arthritis? ›
RA causes inflammation. In response, the body releases CRP into the bloodstream. Doctors measure CRP levels as part of the diagnosis and management of RA. While many factors influence a person's CRP levels, and there is no definitive normal range, CRP levels above 10 mg/l suggest substantial inflammation.Can high CRP cause fatigue? ›
Low-grade inflammation can lead to fatigue. Higher CRP was linked with fatigue – both in healthy people and in disease-free survivors of breast cancer [27, 28, 29].Is CRP a tumor marker? ›
A few biologic compounds meet the criteria for an ideal tumor marker; C-reactive protein (CRP) is one . It is a non-specific acute phase reactant which reflects tissue damage.Can CRP detect tumor? ›
However, high levels of CRP were found to be strongly associated with advanced disease severity in numerous cancer types (elaborated below). Hence, CRP measurements have potential utility as a diagnostic tool in assessing disease status and progression, including in cancer.What is the number 1 inflammatory food? ›
- Red meat and processed meats, including bacon, hot dogs, lunch meats and cured meats.
- Refined grains, including white bread, white rice, pasta and breakfast cereals.
- Snack foods, including chips, cookies, crackers and pastries.
- Sodas and other sweetened drinks.
There was no significant difference in change in circulating hs-CRP concentration between individuals consuming eggs relative to non-egg consuming controls (MD 0.24 mg L−1, 95% CI: −0.43, 0.90, P = 0.48) with no evidence of heterogeneity between trials (I2: 53.8 %, Q statistics: 15.15, P = 0.03) (Figure 2).Can eggs increase CRP? ›
A CRD with daily intake of eggs decreased plasma CRP and increased plasma adiponectin compared to a CRD without eggs.What are 3 symptoms of inflammation? ›
- Loss of function.
Types of NSAIDs
- high-dose aspirin.
- ibuprofen (Advil, Motrin, Midol)
- naproxen (Aleve, Naprosyn)
When inflammation happens, chemicals from your body's white blood cells enter your blood or tissues to protect your body from invaders. This raises the blood flow to the area of injury or infection. It can cause redness and warmth. Some of the chemicals cause fluid to leak into your tissues, resulting in swelling.
Can high CRP cause pain? ›
Higher levels of CRP were associated with higher pain sensitivity ratings at pain threshold (p = 0.02) and tolerance (p = 0.03) after adjusting for age, body mass index, time to reach pain threshold or tolerance, and clinical pain status.How can I treat CRP at home? ›
Amazing Anti-Inflammatory Foods you Must Add To your Diet –
- Green Tea. ...
- Turmeric. ...
- Berries. ...
- Peppers. ...
- Fatty fish. ...
- Nuts. ...
- Green vegetables. ...
- Olive oil.
CRP is also useful as a laboratory marker to predict prognosis and relapse in patients with Crohn's disease and acute pancreatitis. Elevated CRP levels have been associated with an increased risk of colorectal cancer and are a marker of poor prognosis, indicating more advanced disease and, possibly, reduced survival.Does stress cause high CRP? ›
CRP is elevated in chronic stress and may be the link between stress and low-grade inflammation-related diseases. Scientists found that both psychological and social stress significantly impacts CRP .When should CRP be treated? ›
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.