ASTM D8293-22

Overview

ASTM D8293-22, "Standard Guide for Evaluating and Expressing the Uncertainty of Radiochemical Measurements," provides essential guidance for laboratories and method developers working with radiochemical analysis. Developed by ASTM International, this standard describes best practices for evaluating and reporting measurement uncertainty in the analysis of radionuclide activities in water and other environmental media.

Uncertainty quantification is critical for laboratories to ensure accurate, reliable results when detecting and quantifying radionuclides. With this guide, laboratories can make informed decisions and comply with regulatory and client requirements for radiochemical data quality.

Key Topics

• Fundamentals of Measurement Uncertainty

  • Defines key terms such as error, uncertainty, input and output quantities
  • Explains the difference between error (theoretical) and uncertainty (practical estimate)
  • Emphasizes why measurement results must be accompanied by a quantified uncertainty

• Evaluation and Propagation of Uncertainty

  • Introduction to the law of propagation of uncertainty
  • Procedures for combining multiple sources of uncertainty from measurements and calculations
  • Explanation of Type A (statistical) and Type B (non-statistical) methods for uncertainty estimation

• Correlation and Coverage Factors

  • Guidelines for dealing with correlated measurement inputs, including calculation of covariance
  • Use of coverage factors (k) to report either combined standard uncertainty or expanded uncertainty
  • Reporting practices to clearly specify the type of uncertainty and its associated probability

• Reporting Results

  • Recommendations that every reported radiochemical result includes an explicit uncertainty value
  • Best practices for rounding, expressing uncertainty, and ensuring transparency for data users

• Practical Examples

  • Includes common scenarios such as calibration, sample subsampling, detection limits, and calculation of weighted averages with uncertainty

Applications

ASTM D8293-22 is specifically designed for:

• Environmental Testing Laboratories

  • Measurement of radionuclide activity in water, soil, and other environmental samples
  • Ensuring defensible, comparable, and transparent results for regulatory compliance or public health assessment

• Development of Radiochemical Methods and Software

  • Application of uncertainty evaluation principles in custom or proprietary analytical methods and laboratory information systems
  • Facilitating standardized data output, critical for inter-laboratory comparability

• Regulatory and Quality Assurance Contexts

  • Supports decision-making by providing measurement results with an explicit, estimated uncertainty
  • Meets expectations of best practice as outlined in regulatory frameworks and international lab accreditation standards
  • Especially relevant for laboratories reporting results for drinking water compliance, radiological environmental monitoring, and similar programs

• Education and Training

  • Used as a resource for training laboratory personnel and for clarifying uncertainty concepts to clients or regulators

Related Standards

ASTM D8293-22 draws from and complements several key international and domestic standards, including:

• ASTM E2655 - Guide for Reporting Uncertainty of Test Results and the Use of the Term Measurement Uncertainty in ASTM Test Methods
• BIPM JCGM 100:2008 - Guide to the Expression of Uncertainty in Measurement (GUM)
• Eurachem/CITAC QUAM - Quantifying Uncertainty in Analytical Measurement
• ANSI N42.23 - Measurement and Associated Instrumentation Quality Assurance for Radioassay Laboratories
• ASTM D7902 and E177 - Terminology for Radiochemical Analyses; Practice for Use of the Terms Precision and Bias
• MARLAP Chapter 19 - Provides further radiochemistry-specific uncertainty evaluation guidance

By adopting ASTM D8293-22, laboratories align with globally recognized practices in expressing radiochemical measurement uncertainty, reinforcing credibility and stakeholder confidence in their results.