ASTM_E_2764_-_11.pdf

Designation:E276411Standard Practice forUncertainty Assessment in the Context of Seized-DrugAnalysis1This standard is issued under the fixed designation E2764;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This practice provides guidance on the concept ofuncertainty and its application to the qualitative and quantita-tive analysis of seized drugs.In this context,uncertaintyencompasses limitations of qualitative methods as well asnumerical ranges as applied to quantitative analyses.1.2 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.3 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2E2329 Practice for Identification of Seized DrugsE2327 Practice for Quality Assurance of Laboratories Per-forming Seized-Drug AnalysisE2549 Practice for Validation of Seized-Drug AnalyticalMethods2.2 ISO Standards:3ISO 3534-1:1993 StatisticsPart 1:Probability and GeneralStatistical Terms3.Significance and Use3.1 Application of UncertaintyQualitative and quantita-tive analyses require different approaches,refer to the refer-ences for additional information.Analysts shall understand thelimitations of qualitative and quantitative determinations andhave tools to estimate a value for measurement uncertainty ofrelevant,but not necessarily all,numerical results.In thisregard,efforts should be made to use the vocabulary,symbols,and formatting expressed in documents published by interna-tional standardizing organizations such as ISO and ASTMInternational.3.1.1 An understanding of uncertainty is fundamental to theinterpretation and reporting of results.3.1.2 The term“uncertainty”does not imply doubt;rather,its consideration provides assurance that results and conclu-sions from methods and analytical schemes are fit for purpose.3.1.3 The concept of uncertainty shall be considered forboth qualitative and quantitative results.3.1.4 Laboratory management shall ensure that uncertaintybe addressed through the provision of training,procedures anddocumentation.3.1.5 Laboratory management should consider customerrequirements,such as a request for qualitative versus quanti-tative determinations,which influence the assessment of un-certainty.3.2 The benefits of understanding and determining uncer-tainty in this context include:3.2.1 Enhancing confidence through increased understand-ing of results,3.2.2 Providing a mechanism to express the reliability ofresults,3.2.3 Enabling the laboratory management and customer toevaluate the fitness for purpose of results,3.2.4 Facilitating the identification of procedural limitationsand providing a basis for improvement,and3.2.5 Complying with accreditation requirements.4.Qualitative Analysis4.1 The identification of seized drugs requires the combina-tion of methods to form an analytical scheme(see PracticeE2329).4.2 Individual methods have limitations and,consequently,uncertainty.Uncertainty of qualitative methods is not typicallyamenable to being expressed in numerical terms.4.3 Understanding these limitations enables laboratory per-sonnel to build an appropriate analytical scheme to correctlyidentify a drug or other chemical.1This practice is under the jurisdiction of ASTM Committee E30 on ForensicSciences and is the direct responsibility of Subcommittee E30.01 on Criminalistics.Current edition approved June 1,2011.Published June 2011.DOI:10.1520/E2764-11.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.3Available from International Organization for Standardization(ISO),1,ch.dela Voie-Creuse,CP 56,CH-1211 Geneva 20,Switzerland,http:/www.iso.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 4.3.1 It is expected that in the absence of unforeseen error,an appropriate analytical scheme effectively results in nouncertainty in reported identifications.4.3.2 Relevant limitations of an analytical scheme(forexample,inability to differentiate isomers,unavailability ofreference standard,limits of detection and resolution)shouldbe documented and might need to be included in the report(seereporting examples in 7.2).5.Quantitative Measurements5.1 Quantitative measurements have an associated uncer-tainty,which is defined as“an estimate attached to a test resultwhich characterizes the range o