C-Reactive Protein (CRP)
|What is the purpose of this test:||CRP is a marker of inflammation. The standard test detects inflammation in the body. A similar version of the test, known as hs-CRP (high-sensitivity C-reactive protein), is specifically used to determine a person's risk for cardiovascular disease.|
|How to prepare:||
For the blood sample:
Ideally, CRP should not be detectable in the blood.
Individuals with results < 1.0="" mg/l="" at="" the="" hs-crp="" test,="" have="" a="" low="" risk="" for="" cardiovascular="" disease.="" two="" tests,="" 2="" weeks="" apart="" is="" optimal.="">
If this test was ordered to determine your risk for cardiovascular disease, it is likely that a full lipid profile, including total cholesterol, HDL, LDL and triglycerides , was already performed.
If this test is being used as a marker for infection or inflammation, an erythrocyte sedimentation rate test may also be ordered.
Standard CRP test - This is a general, non-specific test. While an elevated CRP may not shed any light on the nature of the condition, it does confirm the presence of inflammation. The standard test can be ordered if post-operative complications are suspected. It can also be used to monitor inflammatory disease activity (ex: arthritis, ulcerative colitis) and response to treatment.
hs-CRP test - CRP is a substance that is released into the blood in response to inflammation. In patients with cardiovascular disease, only a small amount of CRP is released. Measuring your CRP levels can therefore help assess your risk for cardiovascular disease. Because the amount of CRP associated with cardiovascular disease is much lower than the amount associated with inflammatory diseases, the high-sensitivity C-reactive protein test (hs-CRP) is used since it can detect much lower levels than the standard CRP test.
When should the hs-CRP test be ordered?
The Canadian Cardiovascular Society recommends this test for men over the age of 50 and women over the age of 60 with a cardiovascular risk between 10 and 19% (i.e. intermediate risk) and a C-LDL < 3.5="" mmol/l.="" this="" test="" is="" requested="" because="" studies="" have="" shown="" that="" statin="" therapy="" is="" beneficial="" in="" these="" individuals="" if="" crp="" is="" greater="" than="" 2="" mg/l.="">
What does an abnormal test result mean?
If the result is too high
Standard CRP test - If your levels are elevated, it means that inflammation is present in the body. The inflammation may be the result of an infection (bacterial or fungal), an inflammatory disease (e.g. rheumatoid arthritis, lupus, vasculitis), cancer, etc. Obesity and pregnancy can also raise the CRP level.
hs-CRP test - A result above 1 mg/L may be indicative of cardiovascular disease. If, after several tests, hs-CRP levels are still high (> 10 mg/L) for reasons unknown, the patient should be evaluated to rule out causes other than cardiovascular disease.
Since the standard CRP and hs-CRP tests measure the same thing, individuals with chronic inflammation should not have their hs-CRP level measured since the inflammatory condition will be responsible for the elevated levels.
|1.0 to 3.0 mg/L||Average risk of developing cardiovascular disease|
|3.0 to 10.0 mg/L||High risk of developing cardiovascular disease|
|> 10.0 mg/L||Other cause of inflammation|
If the result is too low
A low result is desired.
|< 1.0="" mg/l="">||Low risk of developing cardiovascular disease|
Factors that can interfere with test accuracy
A person's CRP level can be affected by their failure to comply with test preparation and certain medications such as nonsteroidal anti-inflammatory drugs (e.g. ibuprofen, Aspirin) and estrogens (hormone therapy, birth control pills).
What you should know before going for this test
Before going for a blood test, examination or other, it is always a good idea for you to have a complete list of all prescription and over the counter medications and/or natural products you may be taking. If you are unsure or have any questions, your pharmacist will be able provide you with additional information.
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The patient information leaflets are provided by Vigilance Santé Inc. This content is for information purposes only and does not in any manner whatsoever replace the opinion or advice of your health care professional. Always consult a health care professional before making a decision about your medication or treatment.