C-Reactive Protein (CRP) Test

Produced in the liver, C-reactive protein (CRP) is an acute phase reactant (APR) which begins to increase in serum a few hours after the initiation of an inflammatory process. CRP is a sensitive but nonspecific indicator of acute injury, bacterial infection, or inflammation. Very high CRP values are found in acute myocardial infarction, sepsis, malignancy, autoimmune disorders, and following surgery. Epidemiologic studies have been published linking serum CRP levels to coronary heart disease risk (see High-Sensitivity C-reactive Protein).

Increased C-reactive protein (CRP) levels are found in inflammatory conditions including: 

• Bacterial infection
• Rheumatic fever
• Active arthritis
• Myocardial infarction
• Malignancies and in the post-operative state

This test cannot detect the relatively small elevations of CRP that are associated with increased cardiovascular risk, order our C-Reactive Protein, High Sensitivity test to measure levels associated with cardiac conditions.

Clinical Uses of CRP Test

For several decades CRP levels have been used, somewhat like the erythrocyte sedimentation rate (ESR), as a useful marker of inflammation, both for early detection and activity monitoring.

• Nonspecific indicator or inflammation often used in routine laboratory screening of ill patients.
• Aid in detecting infection and assess antibiotic response to bacterial infection
• Postoperative monitoring: Aids in detecting possible complications (inflammation/infection). By 4-6 hours after a surgical procedure the circulating CRP begins to rise and reaches a peak, by 2-3 days after the operation. Postoperative values exceeding this range are associated with significant complications - usually inflammatory processes.
• Useful as a risk factor for cardiovascular disease - epidemiologic studies have established that individuals with a higher baseline CRP are at increased risk for CHD and stroke. See High Sensitivity C-Reactive Protein, Serum or Plasma
• Aid in detecting, assessing severity, and monitoring inflammatory process of many disease processes or conditions including
  • Myocardial infarction
  • Pelvic inflammatory disease (PID)
  • Sepsis in critically ill patients
  • Acute appendicitis
  • Transplant rejection