Balancing the (uncertainty) budget—postmortem toxicology laboratory conformance to ANSI/ASB Standard 056: <i>Standard for Evaluation of Measurement Uncertainty in Forensic Toxicology</i>

In postmortem forensic toxicology, the accuracy and reliability of toxicological results are critical to the medicolegal death investigation process. ANSI/ASB Standard 056: Standard for Evaluation of Measurement Uncertainty in Forensic Toxicology establishes the minimum requirements for evaluating measurement uncertainty (MU) in quantitative methods utilized in forensic toxicology. Accurate evaluation of MU increases confidence in results, supports scientific rigor, enables inter-laboratory comparability, and ensures legal defensibility. Using the National Institute of Standards and Technology (NIST) 8-step procedure described in ANSI/ASB Standard 056, postmortem forensic toxicology laboratories can develop customized, flexible MU budget templates that accommodate a variety of analytical workflows and sample preparation techniques commonly used in the field. This manuscript highlights the use of a template that is adaptable to both routine quantitative workflows and those employing method of standard addition, providing example MU calculations for each. By aligning laboratory practices with the NIST 8-step procedure, as well as integrating accreditation requirements and published ANSI/ASB Standards into their quality management system, laboratories enhance the accuracy and reliability of their toxicological results. Adhering to ANSI/ASB Standard 056 ensures that the inherent variability in postmortem toxicological analyses is appropriately assessed and managed in a manner consistent with best practices.