From the Guidelines
CRP can be elevated in patients with Lyme disease, particularly in later stages or disseminated disease, but it is not a reliable or specific marker for diagnosing this condition. The elevation of CRP in Lyme disease reflects the body's general inflammatory reaction to the Borrelia burgdorferi infection rather than being specific to Lyme disease itself 1. In early localized Lyme disease, CRP levels may be normal or only mildly elevated. However, in later stages or disseminated disease, particularly when arthritis, carditis, or neurological manifestations develop, CRP levels may increase more significantly as part of the inflammatory response.
Some key points to consider when evaluating CRP levels in the context of Lyme disease include:
- CRP is a non-specific marker of inflammation and can be elevated in a variety of conditions, not just Lyme disease 1.
- Specific serological tests like ELISA followed by Western blot are more appropriate and reliable than measuring CRP for diagnosing Lyme disease 1.
- CRP testing may be useful as a non-specific marker to monitor inflammation and response to treatment once Lyme disease has been diagnosed, but physicians typically rely on clinical symptoms and specific Lyme antibody tests for both diagnosis and monitoring treatment effectiveness.
- The use of CRP in conjunction with other tests, such as ESR and serum interleukin-6, may be helpful in evaluating patients with suspected infection, including those with Lyme disease 1.
It's also important to note that the evidence provided does not directly address the relationship between CRP and Lyme disease, but rather discusses the use of CRP in diagnosing infection in general 1. However, based on the available information, it is clear that CRP is not a reliable or specific marker for diagnosing Lyme disease, and other tests and clinical symptoms should be used to guide diagnosis and treatment.
From the Research
CRP Levels in Lyme Disease
- CRP levels are significantly elevated in early localized and early disseminated Lyme disease, but not in the later stages of active infection 2
- Elevated CRP levels are also found in patients with antibiotic-refractory Lyme arthritis and post-treatment Lyme disease syndrome, suggesting that these conditions are associated with inflammatory mechanisms distinct from those in active infection 2
- A preliminary study found that 86% of patients with Lyme disease had abnormally high concentrations of serum CRP, and that CRP concentration can provide a valuable means for the clinical diagnosis and monitoring of Lyme disease 3
Acute-Phase Response Proteins
- CRP is one of the acute-phase response proteins that are involved in the innate immune response to Lyme disease 2, 4
- Other acute-phase response proteins, such as serum amyloid A (SAA), are also elevated in early Lyme disease, but not in the later stages of active infection 2
- A study found that CRP, along with other proteins, may serve as a candidate blood biomarker for the laboratory diagnosis of early Lyme disease 4
Treatment and Diagnosis
- The diagnosis of Lyme disease is usually made clinically, and treatment is accomplished with doxycycline or amoxicillin 5
- CRP levels may be useful in monitoring the response to treatment, as they have been found to decrease after treatment 3
- However, the relationship between CRP levels and treatment outcome is not fully understood and requires further study 2, 3