CRP was originally named for its ability to precipitate pneumococcal C polysaccharide in the Ca ion environment. It is an acute phase protein synthesized by liver cells when the body is subjected to inflammatory stimuli such as microbial invasion or tissue damage. The CRP molecule contains multiple calcium ion binding sites, one disulfide bond, and 224 amino acids, which are easy to form a disc-like arrangement of five non-covalently bound subunits. CRP is expressed in many organs, most expressed in the liver, and can be detected in various body fluids such as human blood, cerebrospinal fluid, and pleural and ascites.

CRP concentrations in healthy human serum are very low, but during the acute phase response to tissue damage, infection or other inflammatory stimuli, the concentration of CRP in plasma increases greatly. CRP activates complement and strengthens the phagocytosis of phagocytes to play an opsonizing role, removing pathogenic microorganisms invading the body and damaged, necrotic, and apoptotic tissue cells.

Clinical significance

Differential diagnosis of bacterial and viral infections: a slight increase in CRP concentration indicates a viral infection, and a significant increase indicates a bacterial infection;

Prediction of cardiovascular disease: CRP is elevated in acute ischemia and myocardial infarction;

testing for infectious complications;

Observation of the efficacy of antibiotics;

Range: 0.5-200mg/L

Normal CRP<10mg/L

10-25mg/L, suggesting viral infection;

25-50mg/L, indicating bacterial or viral infection;

50-100mg/L, indicating bacterial infection;

>100mg/L, indicating severe bacterial infection;

Profile of CRP