July 18, 2022

What Is a C-Reactive Protein (CRP) Blood Test?

Key Takeaways

  • A CRP blood test measures the level of c-reactive protein in your bloodstream. It is used to diagnose or monitor several conditions that result in inflammation.
  • A CRP test can also be used to predict your risk of heart disease, which can lead to a heart attack or stroke.
  • Your healthcare practitioner may order a CRP test if, based on your medical history and signs and symptoms, you appear to have a serious infection.
  • Fasting is not required before a CRP blood test, however, you should avoid any vigorous exercise, including running, cycling, and weight training.

Your immune system is like your body’s army. It is dedicated to defending your body from anything that may attack. Both day and night, your immune system has your back — literally and figuratively.

Whether the invaders are foreign (from outside the body) or local (from inside the body), your immune system will not give up the fight until all attackers have been eliminated. One member of your body’s army is the C-Reactive Protein (CRP). CRP is produced in the liver and is sent into action when inflammatory conditions are detected within your body and is a marker for inflammation.

A CRP blood test, also known as a high-sensitivity CRP test (hs-CRP test), measures the amount of CRP in your blood. Though this test does not indicate the exact location of the inflammation, it can help your healthcare professional narrow down the type of infection causing high levels of CRP. A CRP test can also be used to predict your risk of heart disease, which can lead to a heart attack or stroke.

In this article, we will explain how a CRP blood test is used, what it is for, and how to interpret the results of this test.

What Is a CRP Blood Test?

CRP is one of a group of special proteins known as acute phase reactants. These are substances that become more concentrated in your bloodstream when inflammation is present in your body. Inflammation is one of the ways your body fights against things that harm it, such as toxins or infection.

A CRP blood test measures the level of c-reactive protein in your bloodstream. It is used to diagnose or monitor several conditions that result in inflammation, including:

  • Fungal infections: such as candidiasis — a fungal infection of the mouth and throat.
  • Bacterial infections: such as sepsis — a potentially life-threatening infection.
  • Autoimmune disorders: such as rheumatoid arthritis and lupus.
  • Inflammatory diseases and flare-ups: such as gout, colitis, and Crohn’s disease.
  • Inflammatory bowel disease: a disorder that results in inflammation and bleeding in the intestinal tract.
  • Bone infections: such as osteomyelitis — an infection that causes inflammation of the bone marrow.

When Should I Get a CRP Blood Test?

Your healthcare practitioner may order a CRP test if, based on your medical history and signs and symptoms, you appear to have a serious infection. For example, if you experience the following symptoms:

  • Viral infection: chills, fever, nasal congestion, sore throat, cough, runny nose, aching joints.
  • Bacterial infection: persistent cough, coughing up phlegm, difficulty breathing, persistent vomiting, blood in urine, vomit or stools, unexplained rash, and swollen lymph nodes.
  • Autoimmune disease: chronic fatigue, joint pain, and swelling, skin problems, digestive problems, abdominal pain, swollen lymph nodes, and recurring fever.
  • Inflammatory disorders: fever, chills, loss of energy, muscle stiffness, headaches, and loss of appetite.

Where Can I Take a C-Reactive Protein Test?

If your doctor has ordered a CRP blood test, they will typically arrange for you to take it at their clinic or a hospital. However, if you would prefer to have your blood sample taken in the comfort and privacy of your home, you also have the option of using a mobile sample collection service like Getlabs.

When you make an appointment with a mobile sample collection service, a specialist will arrive at your home at the appointed time, take your blood sample and then deliver it directly to a local lab for analysis. The service is easy, convenient, and completely confidential.

What Should I Do Before My CRP Test?

Before your CRP test, you should avoid any vigorous exercise, including going for a run, cycling, or weight training. This type of activity can raise your CRP level and affect your test results.

There is no need to fast before a CRP test unless your doctor has ordered additional tests. For example, if your doctor has ordered a CRP test to check for heart disease, they may also recommend a cholesterol test at the same time. In this case, you will need to fast.

Your doctor will consult with you before your test and explain what you need to do.

What Should I Do During My CRP Test?

Each Getlabs’ specialist is dedicated to providing a professional and friendly service. When they arrive at your house, they will introduce themselves and show you their identification. While in your house, they will respect your personal space and privacy at all times.

Before taking your blood sample, your specialist will confirm your identification and ask a few questions about your medical history and general health. After making sure you are sitting comfortably in a chair with armrests or lying down, they will begin the procedure. First, the specialist will examine your arm of choice to find an appropriate vein. This is usually on your forearm. They will sterilize the site for the blood draw with an antibacterial wipe.

Your specialist may tie a tourniquet around your upper arm to help them find a vein. They will then insert a small needle into your vein with a test tube attached to collect your blood sample. Once the sample has been collected, your specialist will remove the needle and apply a bandage to the puncture site. This test is usually completed within five minutes.

What Should I Do After My CRP Test?

After your CRP test, you should rest and avoid strenuous lifting with the arm from which your blood sample was drawn. This type of blood test has very little risk, you may have slight bruising and mild tenderness at the puncture site.

If you notice any of the following side effects, you should contact your healthcare provider as soon as possible:

  • Dizziness or light-headedness
  • Nausea
  • Headache
  • Fainting
  • Infection

How Do I Interpret My CRP Test Results?

Your CRP test results will indicate whether your CRP level is normal or high. The CRP value is expressed in milligrams per deciliter (mg/dL). Although abnormal ranges may vary slightly depending on the laboratory performing the analysis of your sample, typically your results will be within the following ranges:

  • Normal: lower than 10 mg/dL
  • High: 10 mg/dL or higher

If you have an elevated CRP test result, this indicates chronic inflammation and is most likely a sign of a serious infection or chronic disease. In this case, your healthcare practitioner will recommend further tests to clarify the results. If your doctor was using the test as a predictor for your risk factor for heart disease, the results will show the following:

  • Low risk: less than 2.0 mg/L
  • High risk: equal to or more than 2.0 mg/L

Get CRP Testing Done at Home with Getlabs

Like any army, it’s important to routinely check the status of each member to ensure they’re functioning properly and effectively protecting your body. A CRP test can determine if you are suffering from an infection, or to measure your risk of cardiovascular disease. Having a Getlabs specialist take your blood sample means you can have the test done in the comfort and privacy of your home. Our specialist will take your sample to a local lab for analysis straight after the test. You should receive your test results within seven days.

If you would like to find out more about Getlabs, and the wide range of blood tests and other mobile sampling services we offer, contact us today to talk to a member of our team and request more health information.

This page is provided for educational and informational purposes only and does not constitute the provision of medical advice or professional services. The information provided should not be used for diagnosing or treating a health problem or disease, and those seeking personal medical advice regarding any of the tests and conditions referenced above are advised to consult with a licensed clinician. Always seek the advice of your qualified health provider regarding a medical condition and do not disregard professional medical advice or delay in seeking it because of any information on this page. If you think you may have a medical emergency, immediately call 911 or go to the nearest urgent care center or hospital.

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