Assay error detection when using common quality control targets across multiple instruments: An analysis using...

Area of Science:

• Clinical laboratory diagnostics
• Analytical chemistry
• Quality management systems

Background:

• Clinical laboratories often use identical instruments and quality control (QC) rules.
• The optimal approach for QC targets—individual per analyzer or common across all—remains unclear.
• This study investigates the impact of common QC targets on assay error detection.

Purpose of the Study:

• To model the influence of common QC targets on assay error detection and false rejection rates.
• To compare the performance of common QC targets versus individual QC targets on identical instruments.
• To evaluate the real-world consequences using actual QC data.

Main Methods:

• Simulated the effects of bias and imprecision on error detection with common vs. individual QC targets.
• Analyzed QC data from two identical Beckman instruments over six months.
• Utilized over 100 QC data points per instrument for real-world consequence determination.

Main Results:

• Common QC targets showed asymmetrical effects on systematic error detection between instruments.
• If individual assay standard deviations (SDs) differed, common targets increased QC failures on one instrument.
• Common targets reduced error detection by ≥ 0.4 sigma on 33% of tests and caused one instrument's in-control assays to fail over twice as frequently (31% of assays).

Conclusions:

• Common QC targets can decrease the detection of individual assay performance changes.
• Common targets may lead to disproportionately higher QC failure rates on one instrument compared to another.
• Further research is needed to determine the clinical impact of common QC targets.