2007/2008 SWGDRUG 2007/2008 SWGDRUG ACCOMPLISHMENTSACCOMPLISHMENTS

Drug Enforcement AdministrationDrug Enforcement AdministrationOffice of Forensic SciencesOffice of Forensic Sciences

sponsored by the

National Institute of StandardsNational Institute of Standardsand Technologyand Technology

and the

SWGDRUGSWGDRUG

Scientific Working Scientific Working Group for the Analysis Group for the Analysis

of Seized Drugsof Seized Drugs

WHY UNCERTAINTY WHY UNCERTAINTY NEXT?NEXT?

Forensic community asking for guidanceForensic community asking for guidance Accrediting bodies establishing Accrediting bodies establishing

measures of assessing conformity with measures of assessing conformity with ISOISO

Customer requirementsCustomer requirements Jurisdictional requirementsJurisdictional requirements

Transparency (nothing to hide)Transparency (nothing to hide) Potential Exculpatory Information Potential Exculpatory Information

Uncertainty DocumentUncertainty Document The core committee voted in January 2008 to The core committee voted in January 2008 to

release the draft uncertainty document for release the draft uncertainty document for public comment public comment Posted on the website since February 2008Posted on the website since February 2008

The SWGDRUG meeting was held July 21-23, The SWGDRUG meeting was held July 21-23, 2008 in New Orleans, LA2008 in New Orleans, LA

Comments were addressed and the core Comments were addressed and the core committee voted to adopt the document on committee voted to adopt the document on July 22, 2008July 22, 2008

The document should be posted on the website The document should be posted on the website by the end of August 2008by the end of August 2008

SWGDRUG APPROACHSWGDRUG APPROACHTO UNCERTAINTYTO UNCERTAINTY

There is a wealth of information that There is a wealth of information that already exists on Uncertaintyalready exists on Uncertainty No intentions of repeating existing informationNo intentions of repeating existing information

Goal is to tailor the recommendations to Goal is to tailor the recommendations to drug analysis and answer specific drug analysis and answer specific uncertainty questionsuncertainty questions

Answer specific drug analysis uncertainty Answer specific drug analysis uncertainty questions, before others doquestions, before others do

Offer guidance and direction to Offer guidance and direction to laboratories and accrediting bodieslaboratories and accrediting bodies

WHY?WHY? Provide Purpose/GuidanceProvide Purpose/Guidance

Uncertainty is associated with both qualitative Uncertainty is associated with both qualitative and quantitative proceduresand quantitative procedures

Raise AwarenessRaise Awareness Uncertainty is not doubt, it provides assurance Uncertainty is not doubt, it provides assurance

that results and conclusions are fit for purposethat results and conclusions are fit for purpose Laboratory ResponsibilityLaboratory Responsibility

Consider customer requirements and address Consider customer requirements and address uncertainty through training, procedures and uncertainty through training, procedures and documentationdocumentation

BenefitsBenefits Enhanced confidence through increased Enhanced confidence through increased

understanding of resultsunderstanding of results Provides Mechanism to express reliability of Provides Mechanism to express reliability of

resultsresults

HOW?HOW?

Two Primary Two Primary SectionsSections QualitativeQualitative QuantitativeQuantitative

PurityPurity WeightsWeights

QUALITATIVEQUALITATIVE Individual methods have limitations Individual methods have limitations

and, consequently, uncertaintyand, consequently, uncertainty Understanding limitations allows Understanding limitations allows

analysts to build an appropriate analysts to build an appropriate analytical scheme to correctly ID analytical scheme to correctly ID drugs or chemicalsdrugs or chemicals It is expected that an appropriate It is expected that an appropriate

analytical scheme will result in, analytical scheme will result in, effectively, no uncertainty in reported effectively, no uncertainty in reported identificationsidentifications

Relevant limitations of an analytical Relevant limitations of an analytical scheme should be documented and may scheme should be documented and may need to be in reportneed to be in report

QUALITATIVE QUALITATIVE EXAMPLESEXAMPLES

Use Part III B Methods of Use Part III B Methods of Analysis/Drug IdentificationAnalysis/Drug Identification IR and microcrystalline test positive IR and microcrystalline test positive

for cocaine – effectively NO uncertaintyfor cocaine – effectively NO uncertainty LimitationsLimitations

Marquis test positive for Marquis test positive for methamphetamine – could be methamphetamine – could be methamphetamine or other methamphetamine or other amphetaminesamphetamines

GC/MS test positive for ephedrine – GC/MS test positive for ephedrine – could be ephedrine or pseudoephedrinecould be ephedrine or pseudoephedrine

QUANTITATIVEQUANTITATIVE Uncertainty is defined as an Uncertainty is defined as an

estimate attached to a test result estimate attached to a test result which characterizes the range of which characterizes the range of values within which the true value values within which the true value is asserted to lieis asserted to lie

Precise calculations of Precise calculations of measurement uncertainty measurement uncertainty is not always required is not always required

QUANTITATIVE CONT.QUANTITATIVE CONT. Primary numerical values reported in Primary numerical values reported in

the analysis of seized drugs arethe analysis of seized drugs are Weight and PurityWeight and Purity

Where a value is critical, an Where a value is critical, an appropriate measurement uncertainty appropriate measurement uncertainty determination shall be applieddetermination shall be applied Weight close to a statutory thresholdWeight close to a statutory threshold Purity of drug affects sentencingPurity of drug affects sentencing

WEIGHTWEIGHT Uncertainty of a reported value is Uncertainty of a reported value is

dependant on the weighing process. dependant on the weighing process. Factors include:Factors include: Single item versus multiple items (# of Single item versus multiple items (# of

weighing operations)weighing operations) Tare function as separate weighing operationTare function as separate weighing operation Extrapolation of population weight from limited Extrapolation of population weight from limited

sampling of multiple itemssampling of multiple items Aggregate weighingsAggregate weighings Incomplete recovery of material from packagingIncomplete recovery of material from packaging Balance selection (e.g., readability, capacity)Balance selection (e.g., readability, capacity) Balance operation (e.g., sample placement, Balance operation (e.g., sample placement,

environmental conditions)environmental conditions)

PURITYPURITY Sources of uncertainty for purity Sources of uncertainty for purity

determinationdetermination Sampling plan (e.g., handling of multiple Sampling plan (e.g., handling of multiple

exhibits)exhibits) Sample homogeneitySample homogeneity

Analytical methodAnalytical method Sample preparation (e.g., size, matrix effects, Sample preparation (e.g., size, matrix effects,

solubility)solubility) Analytical techniqueAnalytical technique Reference material (e.g., purity of standard)Reference material (e.g., purity of standard) Equipment and instrumentation performance (e.g., Equipment and instrumentation performance (e.g.,

glassware, pipetters, balances, chromatographs)glassware, pipetters, balances, chromatographs) Concentration of analyteConcentration of analyte Environmental conditionsEnvironmental conditions

PURITY APPROACHESPURITY APPROACHES Analytical ErrorAnalytical Error

Address both systematic and random error Address both systematic and random error through method validation and quality through method validation and quality assuranceassurance

Sampling ErrorSampling Error The sample and sampling procedure are The sample and sampling procedure are

often the greatest contributors to often the greatest contributors to measurement uncertaintymeasurement uncertainty

Where appropriate, confidence levels Where appropriate, confidence levels (e.g., 95%) shall be selected based on (e.g., 95%) shall be selected based on considerations relevant to the considerations relevant to the analytical contextanalytical context

Record uncertainty information in Record uncertainty information in validation documents and/or case validation documents and/or case recordsrecords

UNCERTAINTY BUDGETUNCERTAINTY BUDGET All sources of error are separately All sources of error are separately

identified and tabulatedidentified and tabulated Assign values to each error source usingAssign values to each error source using

Empirical dataEmpirical data Validation process, Historical performance data, Validation process, Historical performance data,

Control chart data, proficiency testsControl chart data, proficiency tests Published dataPublished data Combination of empirical and published dataCombination of empirical and published data

Can exclude insignificant sourcesCan exclude insignificant sources Calculate combined and expanded Calculate combined and expanded

uncertainty using significant values for uncertainty using significant values for procedureprocedure

NON-BUDGET APPROACHNON-BUDGET APPROACH Example 1:Example 1: Use of data from replicate Use of data from replicate

analyses from a validated method with an analyses from a validated method with an appropriate sampling planappropriate sampling plan Sources of uncertainty that are separately Sources of uncertainty that are separately

assessed in the budget method are collectively assessed in the budget method are collectively assessed by experimental measurementsassessed by experimental measurements

Example 2:Example 2: Use of two standard Use of two standard deviations (2deviations (2σσ) of the test method results ) of the test method results from reproducibility data from the from reproducibility data from the validation studies.validation studies. Provides an approximation of the Provides an approximation of the

measurement uncertainty for non-critical measurement uncertainty for non-critical valuesvalues

WHEN?WHEN? Reporting of measurement Reporting of measurement

uncertaintyuncertainty Uncertainty shall be Uncertainty shall be

documented but may not documented but may not need to be reportedneed to be reported

Should be reported when Should be reported when result impacts customerresult impacts customer

If not reported, analysts If not reported, analysts shall be cognizant of the shall be cognizant of the uncertainty associated uncertainty associated with their resultswith their results

REPORTINGREPORTING Factors to consider when reporting:Factors to consider when reporting:

JurisdictionalJurisdictional Prevailing statutory requirementPrevailing statutory requirement Relevant governing body (agency) Relevant governing body (agency)

requirementsrequirements Customer requestsCustomer requests Potential exculpatory valuePotential exculpatory value

AnalyticalAnalytical Qualitative results where limitations are Qualitative results where limitations are

known (e.g., inability to differentiate isomers)known (e.g., inability to differentiate isomers) Quantitative measurements where a value is Quantitative measurements where a value is

critical (e.g., weight or purity level close to critical (e.g., weight or purity level close to statutory threshold)statutory threshold)

Laboratory accreditation requirementsLaboratory accreditation requirements

REPORTING EXAMPLESREPORTING EXAMPLES Qualitative:Qualitative:

Contains Ephedrine or Pseudoephedrine. Contains Ephedrine or Pseudoephedrine. Item tested: 5.2 grams net Item tested: 5.2 grams net

Visual examination determined that the Visual examination determined that the physical characteristics are consistent physical characteristics are consistent with a Schedule IV pharmaceutical with a Schedule IV pharmaceutical preparation containing Diazepam. preparation containing Diazepam. There was no apparent tampering of the There was no apparent tampering of the dosage unit and no further tests are dosage unit and no further tests are being conducted.being conducted.

Contains cocaine (salt form not Contains cocaine (salt form not determined)determined)

REPORTING EXAMPLESREPORTING EXAMPLES Quantitative:Quantitative:

Positive for cocaine in the sample tested Positive for cocaine in the sample tested Net weight of total sample: 5.23 Net weight of total sample: 5.23 grams ± 0.03 grams grams ± 0.03 grams Quantitation: 54.7% ± 2.8% Quantitation: 54.7% ± 2.8%

Sample tested positive for cocaine Sample tested positive for cocaine Net weight: 5.23 grams Net weight: 5.23 grams Purity: 54.7% Purity: 54.7% Confidence Confidence Range: ± 2.8%* Range: ± 2.8%* Calculated net weight of drug: 2.8 grams of Calculated net weight of drug: 2.8 grams of cocaine *Confidence range refers to a cocaine *Confidence range refers to a 95% confidence level 95% confidence level

TRAININGTRAINING Individuals responsible for determining, Individuals responsible for determining,

evaluating and documenting uncertainty shall evaluating and documenting uncertainty shall be capable of demonstrating familiarity with be capable of demonstrating familiarity with foundational concepts and principles of foundational concepts and principles of estimating uncertaintyestimating uncertainty General metrology (terminology, symbols, etc.)General metrology (terminology, symbols, etc.) Concepts of random and systematic error, accuracy, Concepts of random and systematic error, accuracy,

precision, propagation of error, etc.precision, propagation of error, etc. Reporting conventions (sig. figs, truncating, Reporting conventions (sig. figs, truncating,

rounding)rounding) Basis statistics (i.e., confidence interval, probability, Basis statistics (i.e., confidence interval, probability,

etc)etc) Analysts shall be capable of explaining their Analysts shall be capable of explaining their

labs procedures for evaluating uncertainty of labs procedures for evaluating uncertainty of qualitative and quantitative analysesqualitative and quantitative analyses

SUPPLEMENTAL SUPPLEMENTAL DOCUMENTS TO FOLLOWDOCUMENTS TO FOLLOW Control chart data methodControl chart data method Demonstration of balance control Demonstration of balance control

using standard weight setsusing standard weight sets Summing weights from individual Summing weights from individual

exhibitsexhibits Expression of sampling uncertainty Expression of sampling uncertainty

based on confidence interval using based on confidence interval using multiple samplingsmultiple samplings

Uncertainty budgetUncertainty budget

CORE COMMITTEECORE COMMITTEE• DEA – Nelson Santos DEA – Nelson Santos (Chair)(Chair)• Secretariat – Scott Oulton Secretariat – Scott Oulton (non-voting)(non-voting)• FBI - Eileen WaningerFBI - Eileen Waninger• ASCLD – Garth GlassburgASCLD – Garth Glassburg• NIST - Susan BallouNIST - Susan Ballou• ASTM and NEAFS- Jack ASTM and NEAFS- Jack MarioMario• Educator – Dr. Chris Educator – Dr. Chris TindallTindall • Educator – Dr. Suzanne Educator – Dr. Suzanne BellBell

CORE COMMITTEECORE COMMITTEE• CAC & NWAFS - Jerry CAC & NWAFS - Jerry MassettiMassetti• MAFS - Richard PaulasMAFS - Richard Paulas• MAAFS - Linda JacksonMAAFS - Linda Jackson• SAFS – Christian MatchettSAFS – Christian Matchett• Toxicology – Dr. Robert Toxicology – Dr. Robert PowersPowers

CORE COMMITTEECORE COMMITTEE• Canada - Richard LaingCanada - Richard Laing• Japan – Mr. Osamu Japan – Mr. Osamu OhtsuruOhtsuru• United Kingdom - Dr. United Kingdom - Dr. Sylvia BurnsSylvia Burns• Australia - Catherine Australia - Catherine QuinnQuinn• Germany - Dr. Udo ZerellGermany - Dr. Udo Zerell• ENFSI - Dr. Michael ENFSI - Dr. Michael BovensBovens• UNODC - Dr. Iphigenia UNODC - Dr. Iphigenia NaidisNaidis

THANK YOUTHANK YOU

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