II. Physiology
- Serum globulin synthesized in the liver
- Acute phase reactant increases with acute tissue injury or inflammation
- C-Reactive Protein binds Bacteria surface and facilitates Phagocytosis
- Rises more than 6 hours after triggering stimulus
- Peaks within 36-50 hours
- Short half life of 5-7 hours
- Rapidly declines after condition resolves
III. Indications
- Detection and monitoring of diseases below
- See efficacy below
- Does not significantly alter management in the emergency detection of serious Bacterial Infection
- Differentiating certain conditions
- Serious Bacterial Infection in children (Occult Bacteremia)
- Systemic Lupus Erythematosus
- CRP higher in Rheumatoid Arthritis
- CRP higher in other Arthritis
- Crohn's Disease
- CRP higher in Ulcerative Colitis
- Pyelonephritis
- CRP lower in cystitis
- Bacterial Infection
- CRP lower in Viral Infection
- Acute Bronchitis
- CRP lower in Asthma
IV. Causes: Increased
-
General inflammatory conditions
- Inflammatory disease
- Infections
- Neoplastic disease
- Inflammatory disease
- Detection and monitoring of infection
- Bacterial Infection in Systemic Lupus Erythematosus
- Neonatal infection
- Postoperative Infection
- Intercurrent infection in Leukemia
- Pyelonephritis
- Detection of Tissue Injury
- Myocardial Infarction
- Transplant Rejection
- Neoplasia (e.g. Burkitt's Lymphoma)
- Cardiovascular disease risk
V. Causes: Normal conditions with elevated CRP
- Medications (e.g. Oral Contraceptives)
- Third trimester of pregnancy
- NSAIDS may modify CRP (increased with Ibuprofen, decreased with Naproxen)
VI. Efficacy
- Serious Bacterial Infection in children
- CRP <10 mg/L has a Negative Predictive Value for Sepsis of 99%
- CRP >40 mg/L is more suggestive of serious Bacterial illness (but not sensitive or specific)
- Bilavsky (2009) Acta Paediatr 98(11): 1776-80 +PMID:19664100 [PubMed]
- McWilliam (2010) Arch Dis Child Educ Pract Ed 95(2): 55-8 +PMID:20351152 [PubMed]
- Yo (2012) Ann Emerg Med 60(5): 591-600 [PubMed]
- Serious Bacterial Infection in adults
- C-RP does not adequately distinguish serious Bacterial Infection in hospitalized adults
-
Septic Arthritis
- CRP is inadequate for ruling-in or ruling-out Septic Arthritis
- CRP >10 mg/ml still has a False Negative Rate of 13% for Septic Arthritis
- CRP >150 mg/ml still has a False Positive Rate of 17% for Septic Arthritis
- Carpenter (2011) Acad Emerg Med 18(8): 781-96 +PMID:21843213 [PubMed]
- CRP closely mirrors infectious process for monitoring
- Sensitivity: 95%
- Kallio (1997) Pediatr Infect Dis 16:411-2 [PubMed]
- CRP is inadequate for ruling-in or ruling-out Septic Arthritis
- Cardiovascular disease
- hs-CRP >3 mg/L predicts more ischemic episodes
- Comparatively weak predictor of heart disease
- Odds Ratio C-RP: 1.45
- Odds Ratio Increased SBP: 1.50
- Odds ratio Tobacco Abuse: 1.87
- Odds Ratio Increased Total Cholesterol: 2.35
- Danesh (2004) N Engl J Med 350:1387-97 [PubMed]
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Related Studies
| Definition (NCI) | C-reactive protein (224 aa, ~25 kDa) is encoded by the human CRP gene. This protein is cleaved during biological activation and is associated with host defense mechanisms and inflammatory responses. |
| Definition (MSH) | A plasma protein that circulates in increased amounts during inflammation and after tissue damage. |
| Definition (CSP) | acute reactive protein that circulates in increased amounts during inflammation and after tissue damage. |
| Concepts | Amino Acid, Peptide, or Protein (T116) , Immunologic Factor (T129) |
| MSH | D002097 |
| SnomedCT | 61425002 |
| LNC | LP15023-2, MTHU002335 |
| English | C-reactive protein, C-Reactive Protein, Protein, C-Reactive, C Reactive Protein, Proteins, specific or class, C-reactive, C-Reactive Protein [Precursor], C-Reactive Protein [Chemical/Ingredient], c reactive protein, c-reactive protein (CRP), CRP, c reactive proteins, Pentraxin 1, Short, Pentraxin 1, C reactive protein, CRP - C-reactive protein, C reactive protein (substance) |
| Swedish | C-reaktivt protein |
| Czech | C-reaktivní protein, CRP |
| Finnish | C-reaktiivinen proteiini |
| Russian | C-REAKTIVNYI BELOK, BELOK C-REAKTIVNYI, C-РЕАКТИВНЫЙ БЕЛОК, БЕЛОК C-РЕАКТИВНЫЙ |
| Croatian | C-REAKTIVNI PROTEIN |
| Polish | Białko C-reaktywne, CRP |
| Spanish | proteína reactiva C (sustancia), proteína reactiva C, Proteína C-Reactiva |
| French | Protéine C-réactive |
| German | C-Reaktives Protein |
| Italian | Proteina C-reattiva |
| Portuguese | Proteína C-Reativa |
Ontology: serum C-reactive protein high sensitivity (C2206053)
| Concepts | Laboratory Procedure (T059) |
| English | serum C-reactive protein high sensitivity, serum C-reactive protein high sensitivity (lab test) |
