C-reactive protein: Difference between revisions
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==Normal Values== |
==Normal Values== |
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*Post-spinal surgery, it peaks at 15 ± 25 a few days after OR |
*Post-spinal surgery, it peaks at 15 ± 25 mg/L a few days after OR |
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*Post-stroke, it can go up to 25 ± 10 |
*Post-stroke, it can go up to 25 ± 10 mg/L |
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*Post-TKA, it can go up to 155 mg/L |
*Post-TKA, it can go up to 155 mg/L |
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*The higher the value, the more likely to be a bacterial infection |
*The higher the value, the more likely to be a bacterial infection |
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**Non-infectious chronic inflammation, such as from smoking, uremia, or cardiac ischemia: 2 to 10 mg/L |
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**Mild to moderate infection such as SSTI, cystitis or bronchitis: increases to 50 to 100 mg/L within 6 hours |
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*Typically beings to rise after 12 to 24 hours and has a half-life of about 19 hours |
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{| class="wikitable" |
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| ⚫ | |||
!Condition |
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!Cutoff |
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!Sensitivity |
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!Specificity |
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!Notes |
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| rowspan="3" |Diabetic foot [[osteomyelitis]] |
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|>10 |
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|0.85 |
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|0.59 |
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| rowspan="3" |near-normal by day 7 to 21 of treatment[[CiteRef::michail2013th]] |
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|>14 |
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|0.84 |
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|0.83 |
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|>17 |
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|0.77 |
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|0.89 |
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|[[Necrotizing soft tissue infections|Necrotizing SSTI]] |
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|>150 |
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|included in LRINEC score |
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|[[Prosthetic joint infection]] |
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|>10 |
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|0.96 |
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|0.92 |
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|[[CiteRef::spangehl1999pr]] |
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|[[Spondylodiscitis]] |
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|normalizes within 3 months of treatment |
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|[[Septic arthritis]] |
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|≥20 |
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|0.92 |
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|[[CiteRef::hariharan2011se]] |
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{| class="wikitable" |
{| class="wikitable" |
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!ESR |
!ESR |
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|high |
|high |
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|low |
|low |
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|rheumatoid arthritis, infection, low albumin elevated creatinine |
|[[rheumatoid arthritis]], infection, low albumin, elevated creatinine |
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|low |
|low |
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* |
*CRP less effected by older age than ESR |
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==Further Reading== |
==Further Reading== |
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Revision as of 01:13, 13 January 2021
Normal Values
- Post-spinal surgery, it peaks at 15 ± 25 mg/L a few days after OR
- Post-stroke, it can go up to 25 ± 10 mg/L
- Post-TKA, it can go up to 155 mg/L
Interpretation
- The higher the value, the more likely to be a bacterial infection
- Non-infectious chronic inflammation, such as from smoking, uremia, or cardiac ischemia: 2 to 10 mg/L
- Mild to moderate infection such as SSTI, cystitis or bronchitis: increases to 50 to 100 mg/L within 6 hours
- Typically beings to rise after 12 to 24 hours and has a half-life of about 19 hours
| Condition | Cutoff | Sensitivity | Specificity | Notes |
|---|---|---|---|---|
| Diabetic foot osteomyelitis | >10 | 0.85 | 0.59 | near-normal by day 7 to 21 of treatment1 |
| >14 | 0.84 | 0.83 | ||
| >17 | 0.77 | 0.89 | ||
| Necrotizing SSTI | >150 | included in LRINEC score | ||
| Prosthetic joint infection | >10 | 0.96 | 0.92 | 2 |
| Spondylodiscitis | normalizes within 3 months of treatment | |||
| Septic arthritis | ≥20 | 0.92 | 3 |
Comparison to ESR
| ESR | CRP | Clinical Scenarios |
|---|---|---|
| high | low | rheumatoid arthritis, infection, low albumin, elevated creatinine |
| low | high | low albumin |
- CRP less effected by older age than ESR
Further Reading
Spine
- Serum C-reactive protein levels correlate with clinical response in patients treated with antibiotics for wound infections after spinal surgery. Spine J. 2006;6(3):311-315.
- CRP better than ESR
Joints
- Serial measurement of the C-reactive protein is a poor predictor of treatment outcome in prosthetic joint infection. J Antimicrob Chemo. 2011;66(7);1590-1593.
- Although the population of patients with failure had higher CRP on average, CRP measurement was not useful for predicting failure in individual patients.
- C-Reactive Protein, Erythrocyte Sedimentation Rate and Orthopedic Implant Infection. PLoS ONE. 2010:5(2):e9358.
- ESR and CRP have poor Sn and Sp for diagnosing hardware infections
- C-reactive protein may misdiagnose prosthetic joint infections, particularly chronic and low-grade infections. International Orthopaedics. 2017.
- 1/3 of culture-positive PJIs had normal CRP and 1/4 had normal ESR.
- Most common associated organisms were coagulase-negative staphylococci and C. acnes
- Seronegative infections in hip and knee arthroplasty: periprosthetic infections with normal erythrocyte sedimentation rate and C-reactive protein level
- 4% of PJI have normal CRP and ESR
- CoNS was more common, Staph. aureus less common
Other
- Prognostic Value of Serial C-Reactive Protein Measurements in Left-Sided Native Valve Endocarditis. Arch Intern Med. 2008;168(3):302-307.
- After 1 week following starting therapy, a CRP over 122 predicts failure (OR 10)
- Utility of C-reactive protein measurements for empyema diagnosis after pneumonectomy. Annals Thoracic Surg. 1994;57(4):933-936.
- Post-operative rise or high-plateau of CRP predicted postoperative infection (empyema)
- Diagnostic Accuracy of C-reactive Protein for Intraabdominal Infections After Colorectal Resections. J Gastrointest Surg. 2009;13(9):1599-1606.
- Post-resection day 3 (or 5 or 7) CRP predicts intraabdominal infection, with Sn 82% and Sp 73% using a cutoff of 190 mg/L (normal <10)
