Assay performance verification and reference interval establishment for PIVKA-II on the Roche cobas e 801

Area of Science:

• Clinical Chemistry
• Immunoassay Technology
• Biomarker Analysis

Background:

• Protein induced by vitamin K absence or antagonist-II (PIVKA-II) is a biomarker relevant to liver health.
• Accurate PIVKA-II measurement is crucial for clinical decision-making, particularly in hepatocellular carcinoma screening.
• Validation of new immunoassay platforms is essential for reliable laboratory diagnostics.

Purpose of the Study:

• To validate the analytical performance of the Roche cobas e 801 PIVKA-II assay.
• To establish age- and gender-specific reference intervals for a healthy adult population in Gansu.
• To evaluate the concordance of the cobas e 801 system with the Abbott Alinity i system.

Main Methods:

• Analytical performance was assessed for precision, linearity, and reportable range according to CLSI and Chinese industry standards.
• Method agreement was evaluated using Passing-Bablok regression and Bland-Altman analysis on 173 samples.
• Reference intervals were determined for 2253 healthy participants using nonparametric methods and decision tree analysis for age stratification.

Main Results:

• The cobas e 801 assay showed excellent precision (CVs < 1.6%) and linearity (R²=0.99), meeting most quality requirements.
• Method comparison revealed significant proportional bias between the cobas e 801 and Alinity i systems.
• Established reference intervals were 9.63-29.10 ng/mL for males and age-stratified for females (9.50-26.30 ng/mL for 18-54 years, 9.42-30.00 ng/mL for ≥55 years).

Conclusions:

• The Roche cobas e 801 PIVKA-II assay demonstrates suitable analytical performance for clinical use.
• System-specific reference intervals are necessary due to observed proportional bias; systems should not be used interchangeably.
• Established local reference intervals aid in targeted decision-making for hepatocellular carcinoma screening.