Validation of accuracy by interlaboratory programme

Area of Science:

• Analytical Chemistry
• Statistical Methods
• Metrology

Background:

• Accurate analytical methods are crucial for reliable scientific and industrial measurements.
• Interlaboratory programs are essential for method validation and ensuring measurement comparability.
• Certified Reference Materials (CRMs) play a key role in accuracy assessment.

Purpose of the Study:

• To propose a statistical design for assessing analytical method accuracy.
• To evaluate the effectiveness of using CRMs in interlaboratory programs for accuracy validation.
• To define criteria for determining practical significance of method bias.

Main Methods:

• Development of a statistical framework for accuracy assessment.
• Application of the design within an interlaboratory testing program.
• Analysis of the difference between certified values and overall method means.

Main Results:

• A statistical design for accuracy validation using CRMs in interlaboratory studies is presented.
• Accuracy validation is based on the difference between the CRM's certified value and the interlaboratory program's overall mean.
• A method's bias cannot be detected if it is smaller than the confidence interval of the CRM's certified value.

Conclusions:

• The proposed statistical design provides a robust method for validating analytical accuracy.
• The study clarifies the limitations of CRMs in detecting small method biases.
• Establishing a threshold for practical significance is key in accuracy validation.