What Causes High CRP (C-reactive Protein) Levels? Blood Test

7 min readJun 13, 2023

Several inflammatory conditions can lead to high CRP levels. A provider may recommend a C-reactive protein test to diagnose if you have inflammation. This test helps measure the amount of C-reactive protein in your blood. Learn more regarding CRP levels, such as the procedure to see these levels, normal ranges, and the causes of high CRP levels in your body.

What is a C-reactive protein?

A C-reactive protein is a protein developed by your liver in your blood. If you experience inflammation, your liver allows CRP to enter your blood vessels. It results in higher CRP levels in the blood. Higher CRP levels can give signals of the presence of inflammation. Different conditions can develop it, occurring from infection to cancer.

A C-reactive protein (CRP) test helps determine the amount of C-reactive protein. A high-sensitivity C-reactive protein (hs-CRP) test is relatively more sensitive than a CRP test. The high sensitivity test can measure little increase of C-reactive protein than a standard test that can indicate the chance of heart problems such as stroke.

Why do you need a CRP test?

If a provider thinks you may carry inflammatory conditions, such as arthritis, cancer, infection, and others, you may need a CRP test.

A healthcare provider may recommend a C-reactive protein test to:

See for the presence of infection
Detect a chronic inflammatory disease, including rheumatoid arthritis
Look for the risk of heart disease
Observe the risk of heart attack
Check how effective the treatment is if you have recently been diagnosed inflammatory disorder

Symptoms of high CRP levels

You may also need to take a CRP test if you experience the symptoms of high CRP levels. The symptoms of elevated CRP levels may vary depending on the medical condition that leads to developing them.

Often people having infections or injuries or conditions, that develop long-term inflammation may feel like symptoms, including

Headache
Pain
Unexpected tiredness
Low level of fever
Nausea
Reduction in hunger
Indigestion
Soreness, weakness, and stiffness in the muscle
Sleep disorders
Weight loss without any efforts

Generally, you will have an acute infection if you are experiencing high CRP levels. Following are the possible symptoms of acute infection, including

Increased heart rate
Breath problems
Lightheadedness
Occurrence of high fever
Sweating or chills that become unmanageable
Vomiting or diarrhea with persistency
An extreme headache, stiffness, or body pain
Appearance of rash
Dry lips, mouth, and skin
Difficulty thinking or concentrating

If you have these symptoms of acute infection or high CRP levels, you should talk with a healthcare provider online.

Relation Between CRP and heart disease

The American Heart Association in 2019 describes that by noticing all risk factors, individuals with CRP levels higher or equal to 2 milligrams per liter (mg/L) may require severe steps to protect against cardiovascular disease.

High CRP levels can help identify people that require closer medical attention or treatment after a heart attack.

CRP levels may provide support in finding people who are at risk of heart disease when the individual cholesterol levels do not give benefits.

What is the procedure for a CRP test?

After scheduling a CRP test, you need to visit the laboratory. A healthcare provider will guide you about collecting the blood sample.

Following are the steps of the procedure of a CRP test, including

You will need to wear off the part of your cloth from one of your arms asked by your provider.
A small needle attached to a test tube will be inserted into a vein in your arm
A small amount of blood will be poured into a test tube.
Your blood sample will be kept at the laboratory for a detailed examination of CRP levels.
After the test, you may resume your daily activities.
The whole procedure generally takes at least five minutes.

How do I get ready for the C-reactive protein test?

A CRP test does not involve a large amount of preparation. On the safe side, you can inform your provider if you use any medications or supplements. Your provider may ask you to stop taking medicines as these may influence your test result. If you need more than one blood test, you may require fasting (avoiding drinking and eating) for several hours.

Risk factors for the C-reactive test

A c-reactive protein is a simple blood test that does not have a high risk. You may feel some pain or sensation during needle injection for blood collection. Other low risks of the test include bleeding, mild infection, and bruising at the puncture site. However, these risks disappear quickly in a short interval.

CRP Test Results

The test results may slightly differ among laboratories due to the use of distinct methods. No fully set standard is built for CRP blood levels. It shows that a little increase in CRP levels does not lead to any problems.

Following are the general recommendations for small, moderate, and elevated CRP levels, including

Small elevation — It occurs between 0.3 mg/dL and 1.0 mg/dL. A little increase in CRP levels may occur in those who are inactive, pregnant, or have chronic diseases like diabetes. Acute infections, including the cold, may also boost the CRP elevation.

Intermediate elevation — It occurs between 1.0 mg/dL and 10.0 mg/dL, which can indicate a severe medical problem. The moderate increase may occur due to acute inflammation, starting from an infection or long-term inflammation developing from a particular disease, including rheumatoid arthritis or heart problems.

Extreme elevation — It lies higher than 50.0 mg/dL. It indicates the signals of acute bacterial infection.

The hs-CRP test often shows the risk of developing cardiovascular disease with a slight increase in CRP levels. The ranges that

Lies below 2 mg/dL lead to a low risk
Lies above 2 mg/dL lead to a high risk

What causes high CRP?

Several inflammatory conditions can cause high CRP levels, such as:

Infection
Cancer
Obesity
Autoimmune conditions, such as rheumatoid arthritis (RA), particular forms of inflammatory bowel disease (IBD) like Crohn’s disease and lupus
Injury to the organ
Pericarditis (inflammation of the heart lining)

High CRP levels usually indicate a current medical problem. A little and intermediate increase of 0.3 to 1 milligram per deciliter (mg/dL) may develop in pregnant women and individuals having diabetes, infections (mild), and a few other medical problems.

One of the leading causes of high CRP levels is severe infection. Uncontrolled autoimmune disease and tissue damage are also responsible.

If a provider thinks you are at risk of heart disease or stroke, you may need to order a hs–CRP blood test besides other tests.

Factors Affecting CRP Levels

A wide range of problems can lead to increased CRP levels. These are the factors that may influence the CRP test result, including

Lifestyle — If you smoke, are overweight or obese, or do not do any physical activity, you may have CRP levels than recommended.

Chronic diseases — Certain conditions that can lead to developing constant inflammation, such as autoimmune diseases, can hide other potential causes of high CRP, like a mild infection.

Pregnancy — Pregnancy may also increase CRP levels, specifically at the later stages.

Changes in estrogen levels — Taking medications based on estrogen, including birth control pills and hormone replacement, may increase CRP levels.

Infection or injuries — These problems may lead to temporarily increased CRP levels, which may hide other possible conditions, like diabetes or Irritable bowel syndrome (IBS).

A healthcare provider will generally recommend a CRP test besides other tests to analyze the overall health condition of a person. You may also repeat the CRP test to monitor the changes in CRP levels with time before proceeding to a diagnosis.

Despite outside or external factors, CRP levels greater than 10 mg/dL generally show an inflammatory problem.

What other things need to consider with the CRP test?

You may need immediate medical care If your test results show high CRP levels. But, if your CRP level is moderately high, finding the cause can be more trouble, specifically if you have no symptoms. A healthcare provider may suggest the following:

Other tests to find the possible causes
Repeating testing within a one to two months time period
Looking for the presence of symptoms

A provider may also ask about your medical history and the recent signs and symptoms you carry because this detail helps in the diagnostic process.

Conclusion

C-reactive protein (CRP) is a substance that is produced by your liver when you experience inflammation. If a healthcare provider thinks you carry a high amount of inflammation, you may need to take a CRP blood test. It is one of the ways to help detect the cause of the inflammation. A CRP blood test does not tell the exact reason for the inflammation in your body, a healthcare provider can utilize it to understand your problem.

In a few cases, elevated CRP does not need any medical care. It often occurs due to short-term elevation due to pregnancy, physical injury, or a mild infection. Rarely, high CRP levels can be a risk factor for developing cardiovascular disease.

Speak to a healthcare provider online if you have the symptoms of high CRP levels or have an inflammation that does not go away for a long time. Many conditions can develop mild or moderate high CRP levels, but elevated CRP levels can be easier to judge.