[False elevations of C-reactive protein: When should they be considered?]

Area of Science:

• Clinical Chemistry
• Immunology
• Laboratory Medicine

Background:

• C-reactive protein (CRP) is a critical biomarker for inflammation.
• Elevated CRP without clear cause suggests potential diagnostic challenges.
• Immunoturbidimetry assays for CRP are susceptible to analytical interferences.

Purpose of the Study:

• To review literature on analytical interferences in CRP measurements.
• To highlight the impact of false positive CRP results on patient care.
• To discuss methods for identifying and mitigating CRP assay interferences.

Main Methods:

• Literature review based on three case studies of CRP interference.
• Analysis of common interference mechanisms, particularly rheumatoid factor.
• Discussion of diagnostic techniques for interference detection.

Main Results:

• Rheumatoid factor binding to capture antibodies is a frequent cause of false positive CRP results.
• Analytical interferences can lead to unnecessary investigations and treatments.
• Accurate CRP measurement is crucial to avoid patient harm and healthcare costs.

Conclusions:

• Persistent, unexplained high CRP warrants suspicion of analytical interference.
• Collaboration between clinicians and lab professionals is essential for accurate diagnosis.
• Identifying and addressing interferences prevents misdiagnosis and inappropriate patient management.