Decrease in the internal quality control intermediate reproducibility imprecision of Cystatin C results in China in...

Area of Science:

• Clinical Chemistry
• Laboratory Medicine
• Quality Control

Background:

• Internal quality control (IQC) data are crucial for assessing laboratory testing performance.
• Cystatin C is a biomarker used for estimating glomerular filtration rate.
• Evaluating intermediate reproducibility imprecision is essential for reliable diagnostic results.

Purpose of the Study:

• To evaluate the intermediate reproducibility imprecision of cystatin C results in Chinese laboratories using IQC data from 2014 to 2023.
• To assess laboratory performance against various established quality specifications.
• To identify trends and differences in imprecision based on reagent manufacturers and analytical platforms.

Main Methods:

• Analysis of IQC data for cystatin C from 255 to 1814 laboratories annually (2014-2023).
• Calculation of coefficient of variation (CV) to measure laboratory imprecision.
• Assessment of pass rates against five performance specifications, including 1/3 total allowable error (TEa) and biological variation (BV).
• Stratified analysis by QC material concentration, reagent manufacturer, and instrument platform.

Main Results:

• Significant decrease in cystatin C imprecision (CV) from 5.1% in 2014 to 3.3% in 2023.
• Upward trend in pass rates based on 1/3 TEa, reaching 88% in 2023.
• Pass rates for BV-based specifications remained below 80% for many laboratories.
• Roche Diagnostics showed low imprecision; BSBE-Abbott Architect achieved 100% pass rate for 1/3 TEa in 2023.

Conclusions:

• Continuous improvement in cystatin C intermediate reproducibility imprecision in China.
• Current BV-based performance specifications for cystatin C may not be universally achievable in Chinese laboratories.
• Significant differences in imprecision exist across various analytical systems, warranting further attention.