The application of theoretical goals based on biological variation data in proficiency testing

Area of Science:

• Clinical Chemistry
• Laboratory Medicine
• Analytical Toxicology

Background:

• Proficiency testing (PT) schemes require defined performance standards for laboratories.
• Establishing acceptable analytical goals for imprecision and inaccuracy is essential for reliable diagnostic testing.
• Current practices often rely on statistical methods or fixed limits, but biological variation offers a more objective basis.

Purpose of the Study:

• To evaluate strategies for defining acceptable performance standards in proficiency testing.
• To emphasize the importance of biological variation in setting analytical goals for laboratory error.
• To advocate for the use of biological variation-based criteria in PT schemes.

Main Methods:

• Review of existing strategies for setting performance standards in PT.
• Analysis of available data on the biological variation of various analytes.
• Comparison of parametric statistical approaches versus empirical fixed limits for data analysis in PT.

Main Results:

• A consensus suggests imprecision (standard deviation or coefficient of variation) should not exceed half of the intraindividual biological variation.
• Biological variation data is increasingly available, facilitating the establishment of objective analytical goals.
• Empirical fixed limits of acceptability show advantages when based on objective biological variation goals.

Conclusions:

• Biological variation provides a robust foundation for setting total laboratory error goals.
• Objective, biologically-based criteria enhance the effectiveness of proficiency testing schemes.
• Adopting biological variation-based goals improves the accuracy and reliability of laboratory test results.