From the Guidelines
A workup for elevated C-reactive protein (CRP) should begin with a thorough history and physical examination to identify potential causes of inflammation, as recommended by the CDC/AHA workshop on markers of inflammation and cardiovascular disease 1.
Initial Evaluation
The initial evaluation should include a complete blood count, comprehensive metabolic panel, and urinalysis to screen for infections, kidney disease, or liver dysfunction.
- Additional targeted tests based on clinical suspicion may include:
- Blood cultures for suspected infection
- Chest X-ray for respiratory conditions
- Joint fluid analysis for arthritis
- Cardiac testing (ECG, troponin) if cardiovascular disease is suspected
Further Testing
For patients with persistent elevation without obvious cause, consider:
- Autoimmune disease testing (ANA, RF, ESR)
- Imaging studies like CT or MRI of areas of concern
- Consultation with specialists such as rheumatology or infectious disease It's essential to remember that CRP is a non-specific inflammatory marker that can be elevated due to numerous conditions, including infections, autoimmune disorders, malignancies, cardiovascular disease, obesity, and even smoking, as noted in a study on the role of biomarkers in surgery 1.
Interpretation of CRP Levels
The degree of elevation may provide clues, with very high levels (>100 mg/L) often suggesting bacterial infection, while moderate elevations may indicate chronic inflammatory conditions.
- A study on excluding or not excluding CRP values higher than 10 mg/L suggests that additional steps could be taken to increase confidence that CRP values >10 mg/L are indicative of an acute immune challenge 1.
Treatment and Follow-up
Treatment should target the underlying cause rather than the CRP level itself, and follow-up testing should be performed to monitor response to therapy, as recommended by the CDC/AHA workshop on markers of inflammation and cardiovascular disease 1.
From the Research
Workup for Elevated CRP
Elevated C-reactive protein (CRP) levels can indicate inflammation in the body, which may be associated with various diseases, including cardiovascular disease, autoimmune diseases, and cancer 2, 3, 4. The workup for elevated CRP typically involves a combination of medical history, physical examination, laboratory tests, and imaging studies.
Possible Causes of Elevated CRP
Some possible causes of elevated CRP include:
- Cardiovascular disease: Elevated CRP levels have been linked to an increased risk of cardiovascular disease, including heart attacks and strokes 3
- Autoimmune diseases: CRP can be elevated in autoimmune diseases such as rheumatoid arthritis, lupus, and multiple sclerosis 4
- Infections: Bacterial and viral infections can cause elevated CRP levels 5
- Cancer: Elevated CRP levels have been linked to an increased risk of certain types of cancer, including lung, breast, and colon cancer 2
Diagnostic Approach
The diagnostic approach for elevated CRP typically involves:
- Medical history and physical examination to identify underlying medical conditions that may be causing the elevated CRP
- Laboratory tests, such as complete blood count, blood chemistry tests, and inflammatory marker tests (e.g., erythrocyte sedimentation rate)
- Imaging studies, such as X-rays, computed tomography (CT) scans, or magnetic resonance imaging (MRI) scans, to evaluate for underlying conditions such as infections or cancer
Management of Elevated CRP
The management of elevated CRP depends on the underlying cause and may involve:
- Antibiotic therapy for bacterial infections 5
- Anti-inflammatory medications, such as corticosteroids, for autoimmune diseases or other inflammatory conditions 6
- Lifestyle modifications, such as diet and exercise, to reduce inflammation and improve overall health
- Monitoring of CRP levels to assess response to treatment and adjust therapy as needed 2, 3, 4