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Dr. Sarah Kerrigan Director, Forensic Science Program, SHSU Laboratory Director, SHSU Regional Crime Lab The Texas Criminal Justice Integrity Unit & The Texas Forensic Science Commission Joint Conference on Forensic Science Austin, TX June 4-5, 2012
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Analytical challenges Alcohol vs. drug toxicology issues Laboratory service challenges Interpretive issues Scientific testimony challenges 2
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Drugs and Poisons in Biological Samples Three sub-disciplines: Human performance toxicology Postmortem forensic toxicology Forensic urine drug testing 3
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Drugs and Poisons in Biological Samples Three sub-disciplines: Human performance toxicology Postmortem forensic toxicology Forensic urine drug testing 4
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Drugs and Poisons in Biological Samples Three sub-disciplines: Human performance toxicology Postmortem forensic toxicology Forensic urine drug testing 5
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“Behavioral toxicology” How drugs influence human performance or behavior Criminal context - Performance Impaired driving Drug-facilitated sexual assault Other criminal acts while under the influence of a drug Death investigation 6
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7 TestInterpretTestify
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Why are the results different (lab to lab)? Why does it take so long for drug toxicology? When should a sample receive drug testing? Toxicology of new designer drugs? 8
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Alcohol Gas chromatography- Flame Ionization Detection (GC-FID) Headspace GC Standardized methodology Well established and accepted Drugs Two-step process Screening (often “immunoassay”) Confirmation e.g. GC- MS Many procedures (many drugs) Well established and accepted 9
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Antibody-based test (immunoassay) Defined “cutoffs” Know what these are Know what drugs are included in the screen Limited scope False positives & negatives possible Not forensically defensible without confirmation 10
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11 POSITIVE e.g.100 ng/mL
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12 NEGATIVE POSITIVE e.g.100 ng/mL
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Gas chromatography-mass spectrometry (GC-MS) or similar Sensitive and specific Used for qualitative (present) and quantitative testing (how much?) Forensically defensible Typically report drugs if they are detectable and/or meet specific criteria Broad scope (hundreds of drugs) Requires separation of the drug from the matrix (e.g. blood) Labor intensive Expensive 13
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Methodology widely accepted Extensive scientific/published literature Results may vary between laboratories Sample storage/degradation (biological matrix) Scope of testing Cutoffs vary between labs Equipment/resources at the laboratory Limits of detection/analytical capabilities Policies/procedures regarding testing protocols 14
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Packaging Chain of custody Sample storage Specimen integrity Collection Preservation Services requested by client (non-scientist, i.e. law enforcement) 15
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Psychedelic Amphetamines (e.g. “Bath Salts”, “Plant Food”) Synthetic Cannabinoids (e.g. “Spice”) 16
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Sold as an incense “Not for human consumption” Many are structurally unrelated to THC (tetrahydrocannabinol) Developed for clinical use initially (CB-2, TBI) Synthetic cannabinoids that bind to CB-1 receptors produce THC-like effects Routine testing in controlled substance exhibits Limited testing in toxicology samples Limited studies in humans to date Growing area of concern/research Large number of substances, complex metabolism 17
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Novel synthetic amphetamines (cathinone derivatives) Synthetic derivatives of “Khat” or cathinone Complex array of adrenergic (stimulant) and hallucinogenic effects Unregulated until recently (some, not all) Routine testing in controlled substance exhibits (e.g. pills, powders) Limited testing in toxicology samples Relatively few clinical studies Growing area of concern/research 18
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Synthetic cannabinoids accounted for only 2.7% of all controlled substance findings (N=586). Synthetic cathinones accounted for only 1.5% of all controlled substance findings (N=323). 19
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Complex biological matrices Isolate the substances prior to analysis Purification process (extraction) is labor intensive Specific procedures for isolation each drug or class of drug Specific procedures for analysis each drug or class of drug Results subject to technical/administrative review 20
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Drug impaired driving likely underestimated (not all specimens are tested for drugs) Drug impaired driving may account for 15- 50% of impaired driving investigations nationally Drug impaired driving inherently more complex than alcohol impaired driving 21
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Alcohol Notably the most prevalent drug in impaired driving Effects, properties and pharmacokinetics are well understood Produce predictable effects in a dose- dependent manner Per-se approach Drugs Prevalence not well understood (likely underestimated) Many drugs involved (hundreds) Effects are less predictable Requires proof of impairment (TX) 22
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What level of [DRUG] is equivalent to a.08? Any level of [DRUG] indicates impairment Quantitative vs. Qualitative toxicology reports (Do you need a NUMBER?) Interpretation based upon lab report in isolation? Polypharmacy issues – multiple drug/alcohol combinations Why is the report NEGATIVE? Cutoffs? Scope of testing? 23
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10 million people reported driving after illicit drug use Drugs (other than alcohol) found in 17.8% fatally injured drivers Drugs detected in up to 40% of injured drivers requiring medical treatment Drug use among drivers arrested for motor vehicle offenses is 15-50% Driving under the influence of drugs (DUID) is highly significant SAMHSA – Substance Abuse and Mental Health Services Administration NHTSA – National Highway Traffic Safety Administration
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Inherently more complex (scientifically and legally) than alcohol-related DWI Fewer studies than for alcohol Requires toxicologists with specialized training to interpret effects Drug impairment is determined on a case-by-case basis Significant number of DWIs - under-reported (testing), under-recognized (training) Drug use and traffic safety is a significant public health and safety concern for all 25
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Proof of impairment “incapable of driving safely”, “under the influence”, “impaired to the slightest degree”, “normal use of mental/physical function”, or otherwise affected by a drug Per-se Level of substance above which driving is prohibited Zero Tolerance Criminal offense to have a specified drug or metabolite in the body while operating a motor vehicle Combination of SCIENTIFIC and LEGAL variables may influence how we interpret a case 26
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28 Illicit Therapeutic Over-the- counter
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Cannabinoids Marijuana CNS Depressants Sedative-hypnotics, muscle relaxants, antidepressants, antihistamines, anticonvulsants, antipsychotics, anxiolytics CNS Stimulants Cocaine, methamphetamine, etc Narcotic Analgesics Morphine, codeine, hydrocodone (Vicodin), oxycodone (Oxycontin), methadone, fentanyl etc 29
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Alcohol The mean BAC (all requests) was 0.15 g/100mL (N=1,373) The mean BAC in alcohol-related DWI investigations (BAC>0) was 0.18 g/100mL (N=1,136) More than one third (34%) of cases submitted by Montgomery County agencies receive drug testing (BAC < 0.1 g/100mL) 30 Drugs Total of 1,388 drug toxicology findings (drugs reported) in 461 cases The average number of drugs reported per case was 3 and the range was 0 to 15 Five most common substances reported: 1. Hydrocodone (Vicodin) 2. Cannabis (THC or THCA) 3. Carisoprodol (Soma) and/or metabolite 4. Alprazolam (Xanax) 5. Diazepam and/or metabolite(s)
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Expensive Costs increase with increased scope Multiple drug use is common Labor intensive Turnaround times Policy/Administrative decisions to balance resources, manage backlogs etc 31
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Average turnaround time (TAT) is 17 days for all cases (N=4,299) 32
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1. Any drug that can affect the brain’s perception, collection, processing, storage or critical evaluation processes 2. Any drug that affects communication of the brain’s commands to muscles or organ systems that execute them For the most part, drugs that affect the central nervous system (CNS) 33
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More complex Often in combination with other drugs and/or alcohol (additive or synergistic effects) Scientific literature is complex May require a toxicologist to interpret the results and provide an opinion These complex issues must be explained to the court using every day language 34
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Multiple drug use Tolerance (chronic vs. naïve) Health Metabolism Individual sensitivity/response Phase of use, withdrawal Put in context of case e.g. environmental factors, conditions Other factors (e.g. distraction, injuries, disease) Typically requires more information than the toxicology report alone 37
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Confusion Poor divided attention Sedation Droopy eyelids Slowed reaction times Memory effects HGN Poor balance Poor coordination Unsteadiness Slurred speech Disorientation Low b.p. Low pulse 39
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DRE Drug Recognition Expert Systematic, standardized, post- arrest procedure 12-step evaluation of behavior, appearance, psychophysical tests, vital signs, eye measurements DRE provides the court with additional information Other Observations Behavior Signs and symptoms Mental and physical functions (SFSTs) Clinical records (EMT, hospital) Driving behavior 41
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Weaving Extreme lane of travel Striking other vehicles Striking fixed objects Slow speed Hit and run Wrong way driving 42
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43 Male, 48y Vehicle swerves into oncoming traffic Speech slurred, watery eyes, HGN present Unsteady on his feet, staggering Poor SFSTs – falls over during OLS, WAT Stated that he swerved “To pick up a tamale” BAC 0.00% Toxicology: Morphine 0.05 mg/L, Meprobamate 20 mg/L Carisoprodol 2 mg/L Oxycodone 0.13 mg/L Hydrocodone 0.06 mg/L Diazepam 0.3 mg/L Nordiazepam 0.3 mg/L Gabapentin, present.
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Choosing the right expert Appropriate sub-discipline of forensic toxicology Appropriate level of training/expertise Training gaps? Need for additional training in forensic toxicology for interpretive testimony….e.g. ”How does this combination of drugs and/or alcohol impair driving?” 44
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Drug Toxicology for Prosecutors American Prosecutors Research Institute, 2004. http://www.ndaa- apri.org/pdf/drug_toxicology_for_prosecut ors_04.pdf http://www.ndaa- apri.org/pdf/drug_toxicology_for_prosecut ors_04.pdf Drugs and Human Performance Fact Sheets, DOT HS 809 725, National Highway and Traffic Safety Administration, 2004 http://www.nhtsa.gov/people/injury/researc h/job185drugs/index.htm http://www.nhtsa.gov/people/injury/researc h/job185drugs/index.htm 46
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