CRP (C reactive protein) C reactive protein is a protein manufactured by the liver and released into the blood within hours of the onset of an inflammatory response (severe bacterial or fungal infection, arthritis, autoimmune disease, inflammatory colon disease, etc.). Depending on the severity of the condition, CRP levels can easily be several hundred milligrams per litre (mg/L) and will fluctuate depending on the efficacy of treatment. Results obtained with this test are generally comparable but clinically superior to those obtained by measuring the sedimentation rate.
Although levels below 5.0 mg/L are considered normal, epidemiological studies have shown that individuals with repeated levels above 3.0 mg/L were 1.5 to 4 times more likely to develop cardiovascular disease (CVD). The CRP test can therefore be used with other CVD risk markers (cholesterol fractions, Framingham risk factor calculation) to better detect these higher-risk individuals. In this context, a result below 3.0 mg/L rules out this possibility, while any result equal to or above 3.0 mg/L needs to be confirmed on a new sample to ensure that the initial high value was not due to a mild inflammatory episode without clinical symptoms or signs.