C-reactive protein (CRP) levels increase and decrease depending on how much inflammation you’re experiencing at any given time. Inflammation is defined as “Redness, swelling, pain, and/or a feeling of heat in an area of the body. This is a protective reaction to injury, disease, or irritation of the tissues.”
When you aren’t sick or injured, it’s normal for C-reactive protein levels to be low. But when something happens to signal to the body that it needs to be healed, levels rise to make this happen. Once you start to recover and symptoms subside, levels will fall and should return to normal.
This is why doctors use CRP tests to determine if a patient’s treatment plan is working, in addition to assessing if he/she is at risk for problems related to chronic inflammation (considered the root cause of many diseases), including heart disease.
What Is C-Reactive Protein?
The definition of C-reactive protein (or CRP), according to the National Institutes of Health, is “a protein made by your liver that is sent into your bloodstream in response to inflammation.”
This molecule is a member of the pentraxin family of proteins. It is secreted mostly by cells in the liver in response to a variety of inflammatory cytokines and can rise very quickly. This happens when the body senses a threat, including an injury or recognition of foreign molecules in the body.
To a lesser extent, CRP is released by muscle cells, macrophages, endothelial cells, lymphocytes, and adipocytes.
Levels of this protein can increase up to 1,000-fold at sites of infection or inflammation.
Emerging research shows that CRP plays important roles in inflammatory processes including by altering pathways involved in apoptosis, phagocytosis, nitric oxide release and production of cytokines.
What can cause C-reactive protein to be high? The No. 1 reason that CRP levels increase is due to inflammation, which is how your body responds to injuries, infections and threats. Research suggests that some underlying causes of inflammation include:
- Bacterial infections, whether mild or severe. CRP in your blood goes up within just a few hours of a serious infection. Infections that can increase CRP include tuberculosis, pneumonia and sepsis.
- Fungal or viral infections
- Inflammatory bowel disease
- Autoimmune diseases
- Bone infections (osteomyelitis)
- Swelling of the blood vessels in the head and neck (called giant cell arteritis)
- Cigarette smoking
- Food allergies that damage the gut lining
- Lack of exercise
- Excessive alcohol use
When C-reactive protein is high, symptoms associated with an inflammatory response occur. These can include:
- Swelling surrounding an injury
- Fever and chills
- Rapid breathing and heart rate
- Nausea and vomiting
- Development of autoimmune disorders, such as arthritis and lupus. These can cause joint swelling and pain, morning stiffness, tiredness, weight loss, and low-grade fevers.-
- Development of other chronic diseases
Is high CRP a sign of cancer? It can be a sign of cancer of the lymph nodes (called lymphoma). This isn’t always the case, as there are many reasons that levels can increase.
What does high C-reactive protein mean for cardiac health? High levels may point to inflammation in the arteries of the heart. This can increase someone’s risk of having a heart attack or developing other cardiac problems, such as coronary artery disease, arteriosclerosis or stroke.
The CRP Test
What is a C-reactive protein test used for? It measures the level of C-reactive protein (CRP) in your blood. This type of test can be performed in both adults and children, and even babies to check for signs of illnesses.
Changes in CRP levels can indicate whether or not treatments you’re receiving are working to manage inflammation. CRP levels often go up until you recover, so if a CRP test detects they are starting to fall, this is a good sign you’re overcoming an infection, injury, etc.
This type of test detects CRP levels, but it doesn’t show where in the body inflammation is occurring, or necessarily what’s causing it.
The test is performed using a blood sample taken from a vein in your arm. You might be told to avoid eating and drinking (to fast) for 8 to 12 hours before the CRP test sample is taken.
After results are obtained, if levels indicate there’s a problem, then other tests might be ordered to figure out what the underlying health issue is. A panel of tests that may be used to help make a diagnosis include: cultures, white blood cell count and differential, erythrocyte count, platelet count, blood glucose and chest radiographs, and physical examination.
Another type of CRP test, called a hs-CRP test, is more sensitive and can detect lower levels of CRP. It is used primarily to screen for heart disease. According to authorities like the American Heart Association, a hs-CRP test is most useful for people who have an elevated risk of having a heart attack within the next 10 years.
Normal CRP Range
Here is a basic C-reactive protein level chart that most healthcare providers use:
- A CRP level under 10 milligrams per liter (mg/L) is considered by some health authorities to be normal. However some recent research shows that any level above 1-2 mg/L may indicate a problem, especially related to heart health.
- Less than 1 mg/L indicates you’re at low risk of cardiovascular disease, while a level between 1 and 3 mg/L means you’re at in increased risk of health problems. Above 3 mg/L is now considered to be an indication of “high risk for cardiovascular disease.”
- Serious bacterial infections usually cause CRP levels to rise between 150 to 350 mg/L.
- Values greater than 100 mg/L can occur due to uncomplicated infections caused by adenovirus, cytomegalovirus, and the viruses that cause influenza, measles and mumps.
- Viral infections usually cause CRP levels to rise to about 20 to 40 mg/L. (much less than with bacterial infections)
What level of C-reactive protein is high in children?
The same values as above apply to children, according to an article published in the journal American Family Physician.
What causes C-reactive protein to be low?
The use of NSAIDs (nonsteroidal anti-inflammatory medicines), aspirin, and steroids can cause your CRP levels to be lower than normal.
How to Treat and Prevent Elevated Levels
C-reactive protein treatment depends on what the underlying cause of the inflammation is. The best way to “naturally” treat high levels is to uncover the root cause of someone’s inflammatory response and then make lifestyle or medication recommendations based on that finding.
The same types of healthy habits that help protect against heart disease, such as eating a balanced diet, not smoking and exercising, are also usually involved in treatment for high CRP levels are.
1. Eat An Anti-Inflammatory Diet
In order to protect against the effects of inflammation on your heart and elsewhere, it’s recommended that you eat a whole-foods diet such as the Mediterranean diet. This type of nutrient-dense diet includes plenty of vegetables, fruits, fresh herbs, fish, whole grains, legumes and nuts.
Eating foods high in antioxidants, such as vitamin C, A and E, plus probiotic foods can help to support your immune system. One study found that high intake of vitamin C (1000 mg/day in supplement form) helped to reduce CRP levels in people with levels greater than 1 mg/L.
It’s also important to address any food allergies you may be suffering from, as well as to avoid foods that trigger flair-ups if you have inflammatory bowel disease. These foods can include: gluten, dairy, caffeine, alcohol and others depending on the person.
2. Get Regular Exercise
Exercise is a powerful way to manage inflammation levels and reduce risk factors for elevated CRP, such as high blood pressure and obesity. A general recommendations for adults is to get at least 150 minutes of moderate exercise per week.
3. Talk to Your Doctor About Your Medication Use
If an infection is the root cause of your elevated CRP, then antibiotics may be needed to help you recover.
Your doctor may suggest that you take certain medications to lower the chances you’ll develop complications, such as a statin/cholesterol-lowering medication or aspirin if you’re at risk for developing cardiovascular disease.
It’s important to work with your provider to manage any existing health conditions that are tied to high inflammation levels. This includes diabetes and obesity for example, as well as high blood pressure and high cholesterol. You may need to take medications to control these risk factors if lifestyle changes alone are not enough, such as diabetes drugs including thiazolidinediones (rosiglitazone and pioglitazone).
You may also need to adjust your use of other medications depending on what tests reveal, such as estrogen/birth control pills or medications that affect inflammation markers.
Additionally, because the use of vitamin C and magnesium supplementation has been shown to help decrease CRP levels, your doctor may suggest trying these.
4. Avoid Other Risk Factors (Like Smoking, Alcohol, Obesity)
Do your best to decrease your risk for having levels of inflammation by avoiding things that overall damage your health. This includes giving up cigarette/drug/alcohol use, maintaining a healthy weight, and treating other health conditions such as diabetes or infections.
Just because your results from a CRP test show that your levels are high doesn’t mean that you should panic. These results also don’t paint a complete picture of your health and need to be combined with other test results.
Work with your doctor to determine what causes may be contributing to your rising levels, including family history of any diseases, use of medications and birth control pills, and your stress level, diet and exercise habits.
- What is C-reactive protein? It’s a protein made in the liver that circulates throughout the body in response to inflammation.
- CRP levels rise when you’re sick or injured, and return to normal (a low level) when you’re healthy and recovered.
- A high level of CRP means you have some type of inflammation in your body, which can be caused by: bacterial, fungal or viral infections, injury, inflammatory bowel disease, autoimmune diseases, allergies, and an unhealthy lifestyle.
- A C-reactive protein blood test is used to determine if levels are high and if treatments are working to lower levels.
- If a CRP test shows levels have increased, treatment involves underlying issues like infections, autoimmune responses, etc. This can involve use of medications, dietary changes and lifestyle changes.