High sensitivity immunoassays for C-reactive protein: promises and pitfalls

Area of Science:

• Clinical Chemistry
• Cardiovascular Medicine
• Biomarker Discovery

Background:

• C-reactive protein (CRP) traditionally detects infection/inflammation using immunoturbidimetric/immunonephelometric methods.
• Automated high-sensitivity CRP (hs-CRP) assays allow measurement at previously unattainable levels in healthy individuals.

Purpose of the Study:

• To explore the clinical utility of hs-CRP in apparently healthy individuals.
• To highlight CRP's role as a predictor of future coronary events.
• To emphasize the need for assay standardization for clinical integration.

Main Methods:

• Utilized prospective study data to analyze CRP levels and cardiovascular event prediction.
• Examined factors influencing hs-CRP assay performance, including precision, sensitivity, matrix effects, calibration, and standardization.

Main Results:

• Elevated CRP levels within normal ranges correlate with age, obesity, smoking, and chronic infections (e.g., Chlamydia pneumoniae, Helicobacter pylori).
• hs-CRP is a strong, independent predictor of future coronary events in diverse populations.
• A proposed risk algorithm combines CRP and lipid concentrations for coronary risk assessment.

Conclusions:

• hs-CRP has significant potential for cardiovascular risk stratification beyond traditional markers.
• Standardization and agreement among hs-CRP assay methods are essential for widespread clinical adoption.
• Addressing assay performance factors is critical for reliable hs-CRP implementation in clinical practice.