Longitudinal evaluation of manufacturer-specific differences for high-sensitive CRP EQA results

Area of Science:

• Clinical Chemistry
• Biomarker Analysis
• Cardiovascular Disease Risk Assessment

Background:

• C-reactive protein (CRP) is a key biomarker for inflammation and tissue injury.
• High-sensitive CRP (hs-CRP) is increasingly used for cardiovascular disease (CVD) risk assessment and monitoring.
• Controversial results in meta-analyses highlight the need to assess hs-CRP assay harmonization.

Purpose of the Study:

• To evaluate the current status of hs-CRP assay harmonization globally.
• To assess manufacturer-specific differences in hs-CRP measurements.
• To consider clinical decision limits for CVD risk stratification.

Main Methods:

• Analysis of data from 17 international external quality assessment (EQA) surveys (2018-2023).
• Inclusion of 2 blinded samples per EQA survey.
• Manufacturer-based approach considering clinical decision limits and result scatter.

Main Results:

• Assay harmonization has improved, with median differences decreasing from 50% to below 20%.
• Coefficient of variation dropped below 10% after a change to single-donor samples.
• Significant assay differences persist, potentially leading to disparate patient classifications.

Conclusions:

• A positive trend towards hs-CRP assay harmonization is observed.
• Meta-analyses should stratify results by assay to account for manufacturer differences.
• Traceability to different international standards may hinder future harmonization efforts.