What is C-Reactive Protein (CRP)?

C-Reactive Protein (CRP) is a protein produced by the liver in response to acute injury, infection, or inflammation.

Elevated levels of CRP are known to be sensitive indicators of inflammation associated with the acute phases of such diseases as rheumatic fever, rheumatoid arthritis and most bacterial and some viral infections. The serum CRP level tends to appear sooner and also subside faster than an elevated Erythrocyte Sedimentation Rate (ESR). Monitoring the CRP level provides valuable information on the progress of a disorder and its treatment.

Why Test for C-Reactive Protein?

CRP is used similarly to Erythrocyte Sedimentation Rate (ESR) as a marker for inflammation. CRP is a nonspecific acute phase reactant used as an indicator of infectious disease and inflammatory states, including active rheumatic fever and rheumatoid arthritis. Progressive increases correlate with increases of inflammation/injury. CRP is a more sensitive, rapidly responding indicator than ESR. CRP may be used to detect early post-operative wound infection, support the differential diagnosis of appendicitis and acute pelvic inflammatory disease, and to follow therapeutic response to anti-inflammatory agents. It may be a useful test to project severity of pancreatitis. CRP rises rapidly, but nonspecifically in response to tissue injury and inflammation. CRP is particularly useful in detection of occult infections, acute appendicitis, particularly in leukemia and in post-operative patients. In uncomplicated post-operative recovery, CRP peaks on the 3rd post-op day and returns to pre-op levels by day 7. It may also be helpful in evaluation of extension or reinfraction after myocardial infarction and in following response to therapy in rheumatic disorders. It may help to differentiate Crohn’s disease (high CRP) from ulcerative colitis (low CRP) and rheumatoid arthritis (high CRP) from uncomplicated lupus (low CRP). Elevated CRP has recently been linked with a two- to five- fold increase in the risk of heart attack.


The ASI CRP Slide Test is a slide agglutination assay for the qualitative and the semiquantitative detection of C-Reactive Protein (CRP) in human serum. No initial dilution of patient samples is required for this test. These materials are intended to be acquired, possessed and used only by health professionals. ASI’s test is not the ultra-sensitive CRP (hs-CRP) test used for predicting cardiac risk.