From the Guidelines
A CRP level of 1.5 mg/L is considered average risk, indicating a moderate level of inflammation in the body. According to the CDC/AHA workshop on markers of inflammation and cardiovascular disease 1, a CRP level between 1.0 to 3.0 mg/L is categorized as average risk. This value suggests that there may be some level of inflammation present, but it is not significantly elevated. C-reactive protein (CRP) is an acute phase reactant produced by the liver in response to inflammation, and normal values typically range from 1.0 to 3.0 mg/L. At 1.5 mg/L, no specific treatment or intervention is needed as this represents a relatively normal physiological state. However, regular monitoring of CRP may be warranted if there's a specific clinical concern or if tracking response to anti-inflammatory treatments.
- Key points to consider:
- CRP results should be expressed only as milligrams per liter and expressed to 1 decimal point 1
- Risk assessment should be modeled after the lipids approach via 3 risk categories: low risk, average risk, and high risk 1
- Other acute inflammatory conditions may result in mildly to moderately increased CRP levels, such as inflammatory bowel disease, rheumatoid arthritis, and long-term alcoholism 1
- Performance goals for CRP measurement need to be developed with a view toward better characterization of the total allowable error required to measure CRP reliably 1
From the Research
CRP Levels and Their Implications
- A CRP level of 1.5 may indicate inflammation in the body, as CRP is a marker of inflammatory conditions 2, 3.
- Elevated CRP levels can be associated with various conditions, including rheumatoid arthritis, infections, and other inflammatory diseases 4, 5.
- In the context of rheumatoid arthritis, a diagnosis is considered if there is at least one joint with definite swelling, and the presence of a rheumatoid factor and/or anti-citrullinated protein antibody, elevated C-reactive protein level, or elevated erythrocyte sedimentation rate is consistent with the diagnosis 4.
Clinical Significance of CRP Levels
- CRP levels can be used to monitor responses to therapy in acute inflammatory conditions, such as acute infections 2.
- Extremely elevated CRP levels (above 500 mg/l) are often associated with severe infections, mainly bacterial, and can have a high mortality rate, especially in patients with active malignancies 5.
- Elevated CRP levels have also been linked to the development of type 1 diabetes, suggesting that inflammation may play a role in the disease's pathogenesis 6.
Interpretation of CRP Results
- CRP levels should be interpreted in combination with clinical history and physical examination, as they lack sensitivity and specificity 3.
- Discordance between ESR and CRP measurements can occur, and various physiological factors can contribute to abnormally high ESR/low CRP readings or vice versa 3.