CRP test: What is CRP Test? What levels of CRP are dangerous?

Inflammation or swelling in the body results from damaged tissues or infections. When the tissues get damaged, the liver cells release C-reactive protein in the blood. 

The c-reactive protein test or the CRP test is a blood analysis to detect the chances of inflammation or swelling. These tests are indicative tests to help understand the extent of any acute or chronic condition of the body causing inflammation. 

This article informs you everything you need to understand about the c-reactive protein or CRP test, the normal CRP levels, and what levels of CRP indicate acute or chronic inflammation of the tissues.

The flu-like symptoms you have been taking for granted could be an early sign of inflammation in the body. It could be due to infections, chronic illnesses, or other undiagnosed complications. Why do you want to live in the dark and not know what’s going on with your body? Make the most out of the medical advancements and book a CRP test to find what’s actually wrong in your body.

CRP test: What is it?

C-reactive protein test or CRP test is a blood marker test to analyse inflammation or swelling in the body tissues. The liver cells produce c-reactive protein or CRP when the body undergoes inflammation or tissue damage. As the degree of inflammation increases in the body, the CRP levels increase tangibly in the blood.  

CRP is an acute-phase protein of hepatic or liver origin that increases following interleukin-6 secretion by macrophages and T cells., which means that its levels rise in response to inflammation. Erythrocyte sedimentation rate (ESR) and blood platelets are the other common acute-phase proteins.

The process of inflammatory responses and the rise of CRP levels in the blood

When tissue damage and infections occur, the immune system promotes the white blood cells (WBCs) to heal the damage. The primary responder cells or cytokines enlarge the blood vessels of the region, allowing more blood, oxygen, and cells to the area. The increased blood flow gradually increases redness, swelling, and inflammation. 

In cases of acute inflammation, this healing process continues for hours or days, causing healthy tissue damage, repair, and problems in the body functions. And in chronic inflammation, the response remains for a long time, and the body goes to a state of high alert as it can contribute to cardiovascular problems, cancer, and other chronic conditions.  

Inflammation is a very complex process involving different cell types. During inflammation, the activities of various cell types increase, initiate, encourage or eliminate inflammation and swelling. 

When inflammation occurs, one of the major changes seen in the blood is the increasing concentration of the acute reactant protein or c-reactive protein (CRP) produced by the hepatic cells. Even in low-grade inflammation, the CRP levels rise. The rise in CRP levels can help determine the extent of inflammation or the grade of inflammation. The CRP circulating in the blood can help predict the possibilities of the body's chronic and acute health conditions, including cardiovascular diseases.

What are the normal and elevated CRP levels in the blood?

CRP is measured in milligrams of CRP per litre of blood or mg/L. The normal or reference range of CRP is anything less than 3 mg/L. CRP levels of more than 3 mg/L indicate inflammation. It is also essential to note that ethnicity, age, and gender also decide the CRP normal levels. CRP values usually increase with age and are high in females and African American descendants.  

Here is a table showing different CRP levels and what these levels of CRP indicate. However, the given CRP ranges can differ between laboratories.

CRP levels	Degree of inflammation	Indications
3 mg/L or less than 3 mg/L	Normal	Common in healthy adults
3 to 10 mg/L	Normal or minor inflammation	Observed during pregnancy, depression, diabetes, overweight, smoking, sedentary lifestyle, or indicate cardiovascular risks
10 to 100 mg/L	Moderate inflammation	Autoimmune diseases, cancers, bronchitis, cardiovascular problems, heart attack
Greater than 100 mg/L	Significant inflammation	Acute bacterial or viral infection, or serious accident/ trauma
Greater than 500 mg/L	Severe inflammation	Acute bacterial infections

CRP levels above 3 mg/L indicate minor infections that can be lowered with medications and lifestyle changes. However, more than 10 mg/L CRP levels are red signals for acute and chronic conditions that require further tests and analysis to determine the precise cause.

Why do you need a CRP test?

C-reactive protein or CRP tests help detect inflammation. Some of the other conditions that require a CRP test include: 

• To identify bacterial infections, severe, life-threatening conditions causing fever with chills, rapid breathing, fast heart rate, nausea, and vomiting. 
• Certain fungal infections
• Inflammatory bowel disorder causes intestinal swelling and bleeding.
• To monitor autoimmune disorder conditions such as lupus or rheumatoid arthritis.
• Osteomyelitis or infection in the bone
• To monitor and assess the effectiveness of ongoing infection treatment.

CRP tests are not done often. However, a few experts recommend CRP level testing routinely and cholesterol tests. People undergoing tests for cardiac risks may require two CRP tests done in a gap of 15 days. 

CRP levels can help assess cardiovascular risk in people with,

• Diabetes mellitus,
• High blood pressure,
• High cholesterol, 
• Excess weight issues,
• And smoking.

CRP levels during COVID-19 infections

CRP levels increase as a result of inflammation and also seem to rise in people infected with SARS-CoV-2. SARS-CoV-2 infection or COVID-19 causes an increased production of inflammatory cytokines and interleukins that help the body fight the viral infection. The increased activity of the immune system can cause damage to lung tissues. The combined inflammatory cytokine action and tissue damage can lead to increased production of CRP from the liver. 

CRP test for SARS CoV2 is not a diagnostic test and only an indicative test for possible inflammation. A significant rise in CRP seen in COVID patients is approximately 20 to 50 mg/L. The high CRP levels in covid patients indicated severe viral infection and lung damage.

How is the c-reactive protein measured? 

The C reactive protein (CRP) is measured by a simple blood analysis where the lab technician uses a syringe to draw a sample of blood from the veins of the arms. There are no specific preparations such as fasting or a liquid diet before taking the CRP blood test. However, one will need to consider certain factors that can affect the CRP levels, such as:

• Medications: Medications such as cholesterol-reducing drugs or statins and nonsteroidal anti-inflammatory drugs (NSAIDs) reduce inflammation and show lower CRP levels during the test. 
• Exercises: Strenuous and excessive exercises can raise the CRP levels. Avoid CRP tests after a strenuous workout regime.   
• Healing injuries or infections: Minor conditions like cuts and infections can temporarily increase CRP levels concealing possible chronic conditions or cardiovascular risks. 
• Supplements: Magnesium supplements are known to lower CRP levels in the blood. Check with your physician about the supplements to take and avoid before the CRP test. 
• Pregnancy and Hormone changes: Pregnant women are likely to have elevated CRP levels, especially during the later pregnancy days. Similarly, women taking oestrogen-based birth control or people undergoing hormone replacement therapies can also increase CRP levels. 
• Other CRP affecting factors: CRP levels rise with increasing age. So, older people tend to have high CRP levels. Similarly, women, smokers, people with diabetes, overweight issues, and depression show higher baseline CRP.

How to lower CRP levels in the blood?

With dietary changes, lifestyle modifications, and medications, you can lower elevated CRP levels by adopting various strategies guided by your physician. Depending on the grade of inflammation and health conditions, a physician may prescribe or suggest the following ways to lower the increased CRP levels. 

• Treatment of the underlying condition: Understanding the reasons for elevated CRP levels is the first step that you should take. Check with your physician and workout out the reason for inflammation in the body. Your physician will help treat the underlying condition that can eventually help reduce the CRP values. 
• Weight Reduction: Obese or overweight people have spiked CRP levels. In such cases, losing weight can help bring down CRP levels. A study shows participants who lost only 5% of their total body weight and fat mass had more than two times the chance of lowering their CRP levels. 
• Exercise: Sedentary lifestyle can also increase CRP levels. Increasing physical activities and a routine of exercise can lower CRP in the blood caused due to sedentary lifestyle. 
• Mental fitness: Mental health can affect the body’s CRP levels. People with depression or a pessimistic mindset show increased CRP. Relaxing, mindful practices, meditation, and yoga can improve mental health and approach.
• Dietary changes: Food plays a significant role in influencing the CRP levels. Multicoloured foods such as apples, avocados, strawberries, cherries, pears, legumes, green leafy vegetables, and broccoli can help lower inflammation and CRP levels.  It is also seen that taking alcohol in small amounts can promote reducing CRP levels than completely avoiding alcohol. Beverages such as coffee and green tea have compounds that can potentially decrease CRP levels and inflammation.

• Supplements: Supplements with omega-3 fatty acids, magnesium, vitamin D, and others can reduce systemic inflammation and CRP levels in the blood. 
• Medications: To treat the underlying conditions causing inflammation, the physician can prescribe medications. If autoimmune conditions or infections are the cause, immune-modulating medications or antibiotics may be prescribed. To reduce baseline CRP, your doctor may suggest angiotensin receptor blockers (ARBs), statin therapies, or cholesterol-reducing medications. 

Frequently Asked Questions

1. What if My CRP is high? 

   If your CRP levels are high, it indicates acute inflammation, infection, injury, or chronic disorder. The physician may recommend additional tests to determine the exact cause or condition causing high CRP levels.

2. Is a CRP of 50 high? 

   Yes. CRP levels of 50 are considered high. CRP levels increase from 10 to 50 mg/L in cases of mild inflammation and viral infections, cardiovascular diseases, autoimmune disorders, or cancer. The CRP values further spikes from 50 to 200 mg/L in case of chronic inflammation and bacterial infections. 

3. Is a CRP of 17 high?

   A CRP level of 10 mg/L and more indicates the presence of inflammation or infection in the body. CRP of 17 mg/L acts as a cut-off mark where CRP levels above 17 show 75% sensitivity and 74% specificity in predicting infections. 

Conclusion

C reactive protein or CRP is released by the liver into the blood when the body tissues undergo damage. The presence of CRP above the normal range in the blood indicates inflammation, and the CRP values decide the grade of inflammation or extent of the infection or disease in the body. The physician may order CRP tests in case of bacterial infection, viral attack, cardiovascular risks, and many others. However, further tests may be required after a CRP to understand the underlying cause or condition.