External quality assessment-based tumor marker harmonization simulation; insights in achievable harmonization for CA...

Area of Science:

• Clinical Chemistry
• Laboratory Medicine
• Biomarker Analysis

Background:

• CA 15-3 and CEA are crucial tumor markers for breast and colorectal cancers.
• Current measurement procedures (MP) for these markers lack sufficient harmonization.
• Inconsistent results hinder reliable clinical interpretation and patient management.

Purpose of the Study:

• To investigate achievable harmonization for CA 15-3 and CEA tumor markers.
• To simulate external quality assessment (EQA) data using patient-pool based samples.
• To evaluate the impact of a defined harmonization protocol on measurement procedure bias.

Main Methods:

• Utilized CA 15-3 and CEA data from SKML, UK NEQAS, and KEQAS EQA programs.
• Defined a harmonization protocol involving MP equivalence and bias assessment (>5%).
• Assessed harmonization status via mean agreement and residual variation (CV %).

Main Results:

• Limited MPs (Abbott, Beckman, Roche, Siemens) were common across EQA programs.
• Recalibration was proposed for Beckman (CA 15-3) and Siemens (CEA) MPs.
• Harmonization reduced CA 15-3 mean bias range from -29.28% to 9.86% to -0.09% to 0.12%.
• Harmonization reduced CEA mean bias range from -23.78% to 2.00% to -3.13% to 1.42%.

Conclusions:

• Significant improvement in CA 15-3 and CEA harmonization is achievable.
• Recalibration of a limited number of measurement procedures is effective.
• Enhanced harmonization supports more reliable tumor marker testing in clinical practice.