The CRP test measures the level of C-reactive protein (CRP) in your blood. CRP is a protein produced by your liver. It is released into your bloodstream in response to inflammation. Inflammation is your body’s way of protecting your tissues if you have been injured or have an infection. Certain autoimmune disorders and chronic diseases can also cause inflammation.

A high CRP level in your blood can be an indicator of inflammation. Various conditions, ranging from infections to cancer, can cause this.

High CRP levels can also indicate inflammation in the arteries of the heart, which can mean a higher risk of a heart attack.

Normally, there are low levels of C-reactive protein in your blood. High levels can be a sign of a severe infection or another disorder.

The CRP test is a highly nonspecific test. CRP levels can rise in many inflammatory conditions.

Why is the CRP Test Performed?

If your doctor suspects that you have an inflammatory condition, such as arthritis, cancer, or an infection, they may request a C-reactive protein test. This test can indicate a high level of inflammation, but it does not show where the inflammation is or what may be causing it.

If you have a previously diagnosed inflammatory problem, your doctor may occasionally request this test to see how your treatment is working and whether the problem is being appropriately managed.

It should be noted that a high-sensitivity C-reactive protein (hs-CRP) test is a slightly different test from a regular C-reactive protein test. This test typically predicts heart disease and stroke.

While a regular C-reactive test can help identify different diseases causing inflammation by measuring high protein levels, the hs-CRP test measures lower (but still high) protein levels that can indicate cardiovascular disease and stroke risk.

If your doctor is focusing on cardiovascular issues, they may request an hs-CRP test.

How is the CRP Test Conducted?

The CRP test is conducted with a blood sample. No special preparation is required for this test. You can eat normally on the day of the test, and it can be performed at any time during the day. However, if your blood sample will be used for additional tests, you may need to avoid eating and drinking for a specific period before the test.

What is CRP Elevation?

Various inflammatory conditions can cause high CRP levels, including:

Specific inflammatory bowel disease types (IBD) such as rheumatoid arthritis (RA), lupus, and Crohn’s disease, as well as ulcerative colitis
Pericarditis, which is inflammation of the heart lining
Infections
Organ and tissue injury
Cancer
Obesity
High CRP levels almost always indicate an underlying serious medical condition. Mild to moderate elevations of 0.3-1.0 milligrams (mg/dL) per deciliter may occur in pregnant individuals and those with mild infections or certain medical conditions such as diabetes.

The most common cause of high CRP levels is a severe infection. Other possible causes include poorly controlled autoimmune disease and significant tissue damage.

What is the Normal CRP Value?

In healthy individuals, the CRP value in a blood test ranges from 0 to 0.5 mg/L.

What are the Symptoms of CRP Elevation?

The symptoms of high CRP levels depend on the underlying condition causing them.

However, many people with mild infections or injuries or conditions causing chronic inflammation may experience similar symptoms, including:

• Unexplained fatigue
• Pain
• Muscle stiffness, pain, and weakness
• Low-grade fever
• Shivering
• Headache
• Nausea, loss of appetite, and indigestion
• Difficulty sleeping.
• Unexplained weight loss

Individuals with very high CRP levels are usually experiencing an acute infection.

• Symptoms of an acute infection include:
• High fever
• Rapid heartbeat
• Uncontrolled sweating, shaking
• Uncontrolled or persistent vomiting, retching, or diarrhea
• Difficulty breathing
• Rash or hives
• Dizziness
• Severe headache, body aches
• Loss of consciousness

In some individuals with elevated CRP levels, especially in the early stages of heart disease, there may be minimal or no symptoms.

Interpreting the Results

Interpreting mildly or moderately elevated CRP levels can be challenging.
Various conditions can cause a slight increase in CRP levels. Since there is no standard reference range for CRP, it is generally not possible to draw any conclusions solely based on CRP levels.
The following factors can also make interpreting CRP levels difficult:

• Lifestyle: Individuals who smoke, are obese, or engage in minimal exercise may have CRP levels higher than normal.
• Minor injuries or infections: These conditions can temporarily raise CRP levels and may mask other potential conditions such as diabetes or IBD.
• Chronic conditions: Infections causing chronic inflammation, including autoimmune diseases, may mask other possible causes of elevated CRP, such as minor infections.
• Estrogen levels: Estrogen-based medications such as birth control pills and hormone replacement therapy can elevate CRP levels.
• Pregnancy: Pregnancy can cause an elevation in CRP levels.

A doctor will typically request a CRP test along with several other tests to obtain a comprehensive overview of an individual’s health. Additionally, they may want to repeat the test to observe how CRP levels change over time before making a diagnosis.
However, regardless of other external factors, CRP levels above 10 mg/L typically indicate an underlying inflammatory issue.

The content on our page is for informational purposes only; please consult your doctor for diagnosis and treatment.