C-Reactive Protein (CRP): Testing for Inflammation

To Summarize:

  • CRP stands for C-Reactive Protein
  • CRP is an inexpensive, useful way to assess for inflammation in your body
  • it is quick to respond - meaning in the early stages of inflammation (or infection), CRP will increase
  • CRP will confirm the presence of inflammation, but not it's source - further investigation will always be required
  • There are many interfering factors of CRP: certain medication or other diagnoses can interfere with CRP

C-Reactive Protein (CRP) is a cheap, helpful way we can measure for inflammation in the body. Although it won’t tell us where inflammation is coming from specifically, it does confirm its presence. I often run this test to track disease progression as well as treatment effectiveness.

Testing for Inflammation

Testing provides many important insights into disease: We can use testing to make a diagnosis, track how severe a disease is or how well it’s responding to treatment [1].

Inflammation is an immunological response. We can measure inflammation in a person’s body through various tests. One test for inflammation is C-reactive protein (CRP). Click here to learn about some of the others.

What is CRP

C-reactive protein, or CRP is what we call an acute-phase reactant. That means, CRP will increase in the early stages of inflammation and immune activation [1] [2].

CRP is Non-Specific

A high CRP does not specifically make a diagnosis. It will signify inflammation, or a bacterial infection is present, but will not tell us the source. It does not increase with viral infections [2]. For more about testing specificity is, please click here.

Testing CRP

CRP is a blood test your Naturopath or medical doctor may request.

A normal value is considered anything less than 0.2 mg/dl.

Anything greater than 1.0 indicates inflammation and/or infection [1].

As stated above, CRP is not specific – meaning an elevated CRP confirms presence but not the cause of a disease [2].

Testing for CRP is quite easy, the test itself is stable and not time sensitive nor tricky to assess [1].

Where Does CRP Come From?

CRP comes from the liver during an acute inflammatory process [2]. It is under control of other chemical mediators called IL-1, IL-6, TNF-alpha [1]. CRP is quick to respond to inflammation, which means in the very early stages of infection or inflammation, we would expect CRP to respond, especially when compared to another marker of inflammation called ESR. Learn more about ESR here.

Interfering Factors

When we interpret CRP, it’s important to consider all the external factors which may affect the levels. Not to say testing CRP is useless in these conditions, but we need to consider all contributing factors.

  • Elevated CRP seen with[2]:
    • Hypertension
    • elevated Body Mass Index
    • metabolic syndrome
    • diabetes mellitus
    • chronic infection (gingivitis, bronchitis)
    • chronic inflammation (such as rheumatoid arthritis)
    • low HDL / high triglycerides
    • Cigarette smoking
  • Decreased CRP seen with:
    • moderate alcohol consumption
    • weight loss
    • increased activity/exercise
  • Drugs that may cause increased CRP
    • Estrogens and progesterones [2]
  • Drugs that may cause decreased CRP [2]:
    • Fibrates
    • Niacin
    • statins
    • Salicylates
    • steroids

Diseases Associated with High CRP [2] [3]

The following are conditions and diseases known to see elevated CRP. Bolded items are autoimmune in nature.

  • Rheumatoid Arthritis
  • Systemic lupus erythematosus
  • Reiter syndrome or Reactive Arthritis
  • Inflammatory Bowel Disease (Crohn disease, Ulcerative Colitis)
  • Ankylosing spondylitis
  • Psoriatic Arthritis
  • Behcet’s, Wegener’s Polyarteritis Nodosa (Vasculitides)
  • Polymyalgia rheumatica
  • Acute rheumatic fever
  • Vasculitis syndrome
  • Tissue infarction or damage
  • Acute myocardial infarction
  • Pulmonary infarction
  • Kidney transplant rejection
  • Bone marrow transplant rejection
  • Soft tissue trauma
  • Bacterial infection
  • Postoperative wound infection
  • Urinary tract infection
  • Tuberculosis
  • Malignant disease
  • Bacterial meningitis

Summary

C-reactive Protein (CRP) is one of many inflammatory markers we can test in our blood. It is quick to respond to infection and inflammation. There are many conditions associated with elevated CRP. It’s useful to test as a means of assessing disease progression and response to treatment.

References

About the Author

picture of me, johann de chickera, naturopathic doctor
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Dr. Johann de Chickera works in the cities of Hamilton and Toronto, in Ontario Canada.

His clinical focus lies in Autoimmune Disease. Click here to learn more about Autoimmune Pages.

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