dr. sarah kerrigan forensic science program director...
TRANSCRIPT
Dr. Sarah KerriganForensic Science
Program DirectorSam Houston State Univers i ty
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Forensic Toxicology
What do they all have in common?2
Drugs and Poisons
All substances are poisons; there is none which is not a poison. The right dose differentiates a poison…."
Paracelsus (1493-1541)
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Overview4
What is Forensic Toxicology?
What does a forensic toxicologist do?
Sub-disciplines of forensic toxicology
Forensic toxicologist vs. drug chemist
Types of casework
Examinations and analysis
Testimony and interpretation
Careers in forensic toxicology?
What is a Drug?
A drug can be any chemical agent that affects living processes and has the potential to impair those processes
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What is forensic toxicology?
The application of toxicology for the purposes of the law
Three main sub-disciplines:
1. Human performance toxicology
2. Postmortem forensic toxicology
3. Forensic drug testing (employment)
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Forensic Toxicologist vs. Drug Chemist
Drug Chemist
Seized drugs
“Solid dosage”
Forensic Toxicologist
Drugs in biological specimens or other complex material
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Drug Chemist
Identification of seized drugs (solid dosage analysis) Illicit drugs or substances used in illicit drug
manufacture Clandestine labs (e.g. methamphetamine) Pharmaceutical drugs (diversion i.e. internet) Drug possession, trafficking etc Qualitative (which drug?) and quantitative
(how much?) analysis (sentencing guidelines) Characteristics of drugs (components)
to determine origin Seized drugs rather than drugs in biological
or complex materials
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Drug Evidence9
Toxicologist
Drugs/poisons in biological specimens – e.g. blood, urine, breath, tissues, stomach contents etc
Living (antemortem) and deceased (postmortem)
Casework applications: DWI, sexual assault, homicide, suicide, accidental, unexplained death etc
Illicit drugs, prescription drugs, OTC drugs, dietary supplements, herbals, plants etc
Qualitative and quantitative analysis in BIOLOGICAL fluids, tissues or other complex samples (matrices)
Interpretation of effects – How does this influence a person?
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Forensic Toxicology Evidence11
Solid dosage drug analysis12
What is the substance?
Is it controlled?
What schedule is it?Controlled substances Act (I to V)
What is the purity (adulterants)?
How much is there?
Where is it from?
Drug Analysis
Variety of analytical techniques
Variable discriminating power
Categorized accordingly (A, B, C)
Two main spectroscopic techniques used: Gas Chromatography-Mass
Spectrometry (GC-MS)
Fourier Transform Infrared Spectroscopy (FT-IR)
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Categories of Techniques for Drug Analysis14
Category A Category B Category C
Infrared Spectroscopy Capillary Electrophoresis Color Tests
Mass Spectrometry Gas Chromatography Fluorescence Spectroscopy Nuclear Magnetic Resonance Spectroscopy Ion Mobility Spectrometry Immunoassay
Raman Spectroscopy Liquid Chromatography Melting Point
X-ray Diffractometry Microcrystalline Tests Ultraviolet Spectroscopy
Pharmaceutical Identifiers
Thin Layer Chromatography
Cannabis only:Macroscopic ExaminationMicroscopic Examination
Plant material or extracts of plant material
Chemical (color) tests(Category C)
Microscopic analysis (cystolithic hairs/bear claws)(Category B)
Powders
Color tests
Thin Layer Chromatography
Microcrystalline tests
GC-MS
FTIR
Capillary Electrophoresis(CE)
Color Tests – Marquis Reagent
Above: The Marquis color test to identify heroin. Black tar and powdered heroin are shown.
Color Tests - Sodium Nitroprusside
Above: Sodium nitroprusside color test (Simon’s Reagent) to identify methamphetamine hydrochloride.
Example: Methamphetamine
Marquis Reagent Sodium Nitroprusside
Top Ten List (Seized Drugs)
1. Marijuana2. Methamphetamine3. Cocaine4. No Controlled Substance5. Pseudoephedrine6. Alprazolam7. Hydrocodone8. Oxycodone9. Psilocybin10. 3,4-methylenedioxymethamphetamine (MDMA)
GC-MS
Most widely used technique Forensically defensible Specific Qualitative and quantitative results Labor intensive Many published procedures Gold standard in forensic laboratories Characteristic retention time Characteristic fragmentation Solid dosage AND Toxicology
Step 1: Separation of Components
Step 2: Ionization
Step 3: Separation of Ions
Step 4: Identification25
Characteristic Mass Spectrum26
C8H10N4O2
8x1210x14x142x16
MW 194
Cocaine
Structure Empirical formula C17H21NO4
MW - 303 Fragmentation!
121
m/z 303-121=182
40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360 380 400 420 4400
10000
20000
30000
40000
50000
60000
70000
80000
90000
100000
110000
m/z-->
Abundance
Scan 443 (4.956 min): coc.D\data.ms82.1
182.1
42.1303.2
272.1122.1 152.1
220.9 341.0 404.7 446.4
CH3N CO2CH3
O
O
Methamphetamine
CH2CHNHCH3
CH3
Empirical formulaC10H15N
(10x12)+(15x1)+(1x14) = MW 149
Fragmentation?
40 60 80 100 120 140 160 180 200 220 240 260 2800
5000100001500020000250003000035000400004500050000550006000065000700007500080000850009000095000
m/z-->
Abundance
Scan 253 (3.710 min): METH-COOL.D\data.ms58.1
91.1
39.1 134.1115.0 207.0 281.0
Methamphetamine Fragmentation
CH2CHNHCH3
CH3
m/z 91m/z 58
40 60 80 100 120 140 160 180 200 220 240 260 2800
5000100001500020000250003000035000400004500050000550006000065000700007500080000850009000095000
m/z-->
Abundance
Scan 253 (3.710 min): METH-COOL.D\data.ms58.1
91.1
39.1 134.1115.0 207.0 281.0
Forensic Toxicology30
What is the substance?
What is it used for?
How do we isolate it from the matrix (blood, urine, brain, liver, drink, tuna sandwich…)?
What kind of effect would it have?
How do we interpret the results (in court)?
Did it contribute to death?
Did it impair performance?
Improve performance?
Other effects?
Postmortem Forensic Toxicology
Death investigation casework
Determination of drugs, alcohol, poisons in postmortem specimens
Are substances present in significant quantities to cause or contribute to death?
Many interpretive issues
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Postmortem Forensic Toxicology32
Suspected intoxication deaths IVDUs (injection sites) Pill fragments (GI contents) Pulmonary congestion/edema Other observations consistent with drug use Investigative leads or crime scene info Medical records / pharmacy records Are substance(s) present in biological samples
sufficient to cause or contribute to death?
Postmortem Forensic Toxicology33
Homicides Many homicides drug related Drug use may provide motive Individual under the pharmacologic effect of a drug
may influence likelihood of committing or being victim of a homicide
Accidental Death Impairment issues – traffic fatalities Failure of judgment – “I can fly” ADRs, polypharmacy, pharmacogenomics
Postmortem Forensic Toxicology34
Natural Medication compliance and seizures – e.g.
anticonvulsants present and at what level? Medication compliance in mental illness – e.g.
antidepressants present and at what level?Suicides GSW, hanging etc: Drug use / compliance issues
may provide the pathologist with useful information
Specimens35
Blood Vitreous humor Stomach contents Urine Liver Brain Kidney Spleen Lung Muscle Hair Nails
Analysis
Preliminary Screening of samples (antibody-based kits)
Confirmatory analysis
Isolation of drugs/poisons
Instrumental analysis e.g. Gas chromatography-mass spectrometry (GC/MS)
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Human Performance Toxicology37
What is it? “Behavioral toxicology” How drugs/alcohol influence human performance Routine/non-routine Implications – safety of self/other How we respond to stimuli: mental & physical components Cognitive and psychomotor impairment How these responses differ from the “norm” – i.e. no drug
or no alcohol How much drug, where it goes in the body, what effect does
it have?
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Which Drugs Can Impair Driving?
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
Pharmacology
Pharmacokinetics“What the body does to the drug”
pharmakon = drug/poisonkinesis = movement
Absorption Distribution Metabolism Elimination
Pharmacodynamics“What the drug does to the
body”
Receptor interactions Mechanism of action
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Applications40
Criminal or civil liability
Driving-related tasks (DWI)
Public safety-related issues
Drug-facilitated sexual assault
Child abuse/endangerment
Assault
Homicide
Others
Alcohol & Driving41
Most frequently studied drug and most frequently encountered task – driving while intoxicated (DWI)
Age-old problem 1843 – Railroad employees in NY prohibited from
drinking 1910 – NYC traffic code cited alcohol as a safety
issue 1912 – National Council for Industrial Safety – later
NSC 1914 - National Safety Council (highway safety
interests) – now assumed by National Highway Traffic Safety Administration (NHTSA) – US DOT
Technology – Past to Present42
1900s – Erik Widmark (Sweden) developed protocol to evaluate alcohol-impaired persons
1930s – Rolla Harger (Indiana University) – “Drunkometer” – alcohol in breath
1939 – First DUI legislation in US (Indiana)
1954 – Robert Borkenstein (Indiana University) – “Breathalyzer” – basis for modern BrAC testing
Today – Implied Consent Laws in every state and a per-se level of 0.08 g/dL ethanol in blood
Why the concern?Grand Rapids Study - 1964
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Accident involvement increased rapidly when BAC was >0.05 g/dL
Drivers with BAC of 0.06 g/dL were twice as likely to cause an accident compared with sober drivers
Drivers with BAC of 0.10 g/dL were 6 times more likely to cause an accident
Drivers with BAC of 0.15 g/dL were 25 times more likely to cause an accident
Study was repeated in 2005 by NHTSA
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Psychophysical Tests
Methods of Directly Examining Mental and/or Physical Impairment
“Divided Attention”
Concentrating on more than one thing at a time (Mental Tasks and Physical Tasks)
Standardized Field Sobriety Tests (SFSTs)48
Developed in 70s with funds from NHTSA Testing and scoring standardized through lab
studies and field validation studies Three of the tests selected to show objective
impairment One-leg stand (OLS) Walk and turn (WAT) Horizontal gaze nystagmus (HGN)
Walk and Turn(Divided Attention Test -
Mental Task and Physical Task)
• Instructions Stage • Walking Stage
Walk and Turn - Test50
Divided attention test in 2 stages: instruction and walking
Instructions given while suspect stands one foot in front of another on a line, maintaining balance
Take 9 heel-to-toe steps along line, make a six-step turning motion, 9 heel-to-toe steps back along line
Impairment measured (scored) by “clues” or the failure to perform the task in accordance with instructions
Walk and Turn – Clues
1. Can’t balance during instructions2. Starts too soon3. Stops while walking4. Doesn’t touch heel-to-toe5. Steps off line6. Uses arms to balance7. Improper turn (or loses balance on turn)8. Wrong number of steps
If the suspect scores two or more clues (points) or cannot perform the test – there is a 68% probability that the BAC is 0.1 g/dL or more
Walk and Turn TestCriterion
2 or more clues indicates BAC above 0.10(68% accurate)
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One-Leg Stand(Divided Attention Test -
Mental Task and Physical Task)
• Instructions Stage • Balance and Counting Stage
One Leg Stand - Test54
Divided attention test in 2 stages: instruction and balancing while counting
Instructions given while suspect stands with both heels together, arms at side
Raise one leg approx 6 inches off floor and count rapidly from 1001 to 1030
One Leg Stand – 4 Clues55
1. Sways while balancing2. Uses arms for balance3. Hops4. Puts foot down
If the suspect scores two or more clues (points) or cannot perform the test – there is a 65% probability that the BAC is 0.1 g/dL or more
One-Leg Stand TestCriterion
2 or more clues indicates BAC above 0.10(65% accurate)
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Horizontal Gaze Nystagmus
Involuntary jerking of the eyes occurring asthe eyes gaze to the side.
HGN - Test58
Measures CNS motor pathways by involuntary jerking of eyes
Nystagmus enhanced by alcohol Most sensitive test of the battery of tests Keep head still, follow stimulus (pen) from side to
side Observes for smooth tracking & onset of nystagmus Early onset of nystagmus (closer to center,
smaller angle) greater the BAC
Clue Number 1
Lack of smooth pursuit
Clue Number 2
Distinct and sustained nystagmus at maximum deviation
Clue Number 3
Onset of nystagmus prior to 45 degrees
45o
Horizontal GazeNystagmus Test Criterion
4 or more clues indicates BAC above 0.10(77% accurate)
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HGN – 3 Clues Per Eye63
1. Lack of smooth pursuit2. Pronounced nystagmus at maximum deviation3. Onset of nystagmus prior to 45 degrees
If the suspect scores four or more clues (points) or cannot perform the test – there is a 77% probability that the BAC is 0.1 g/dL or more
Test may be invalid on individuals with certain medical conditions
Predictive Value of SFSTs at 0.10 g/dL64
68% for WAT(i.e. 68% of those judged impaired by WAT test had BAC 0.1 g/dL or more)
65% for OLS
77% for HGN
When all three tests are used in combination, predictive value was 83.3%
Effect of AlcoholCentral Nervous System
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Continuum of depression, not discrete effects
Low BAC - apparent stimulant effect (depression of inhibitory processes)
Increasing BAC: judgment, decision-making, perception, reaction time are impaired.
Impairment develops prior to overt signs of intoxication, ataxia, slurring, loss of balance
Mental/physical abilities diminished well before the appearance of a “classic drunk”
Stages of Alcohol Intoxication(Dubowski)
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Subclinical <0.05%
Euphoria 0.03 - 0.12%
Excitement 0.09 - 0.25%
Confusion 0.18 - 0.30%
Stupor 0.25 - 0.40%
Coma 0.35 - 0.50%
Death >0.45%
Low Dose Alcohol ImpairmentBAC < 0.05
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Dynamic visual acuity (ability to see detail in moving object)
Divided attention(as low as 0.02g/dL)
Complex reaction time(ability to discriminate among stimuli and respond appropriately as quickly as possible)
Voluntary eye movements(impaired tracking of moving objects)
Moderate Dose Alcohol ImpairmentBAC 0.05 to 0.08
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Attention Vigilance Tracking Information processing
(some reports indicate impairment above 0.02%) Judgment - decision making, risk-taking,
emergency response Reaction time Psychomotor performance Increased Errors - steering, braking, position,
speed, acceleration
Alcohol Impairment0.08
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Performance of driving-related tasks decreases at BACs above zero
“It seems that there is no lower threshold level below which impairment does not exist for alcohol” Moskowitz & Robinson, DOT HS 807 280, 1998
“The National Safety Council Committee on Alcohol and Drugs takes the position that a concentration of 80 milligrams of ethanol per 100 milliliters of whole blood (0.08%w/v) in any driver of a motor vehicle is indicative of impairment in his driving performance”,1971.
Why 0.08? – The SCIENCE70
Virtually all drivers, including experienced drinkersare impaired at a BAC of 0.08 (based on a review of nearly 300 scientific studies)
Critical driving tasks are impaired at 0.08 or below
Divided attention 0.02 g/dL Tracking 0.05 g/dL Reaction Time 0.05 g/dL
Illicit Therapeutic Over-the-counter Herbals or
dietary supplements in some states
Drugs and Driving73
11 million people reported driving after drug use (SAMHSA, 2003)
Drugs (other than alcohol) found in 17.8% fatally injured drivers (NHTSA)
Drugs detected in 10 to 22% of drivers involved in crashes, often in combination with alcohol
Drugs detected in up to 40% of injured drivers requiring medical treatment
Drug use among drivers arrested for motor vehicle offenses in the range 15-50%
Highest rates reported among those arrested for impaired or reckless driving
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Which Drugs Can Impair Driving?
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
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Effects of Drugs on Driving
CoordinationEffects on nerves/muscles -steering, braking, accelerating, manipulation of vehicle
Reaction TimeInsufficient response - reaction
JudgmentCognitive effects, risk reduction, avoidance of potential hazards, anticipation, risk-taking behavior, decreased fear, exhilaration, loss of control
TrackingStaying in lane, maintaining distance
AttentionDivided, not focussed. Time-shared task with high demand for info processing
Perception90% of info processed while driving is visual. Glare resistance, recovery, dark and light adaptation, dynamic visual acuity
77Drug Impaired Driving and Young People: 18% of 21-year olds report drugged driving at least once in the past year
Drug vs. Alcohol DWI78
Statutory schemes vary There are no “per se” drug
concentrations for drugs other than alcohol that are widely accepted by the scientific community
Drug impairment is determined on a case-by-case basis
Inherently more complex (scientifically and legally) than alcohol-related DWI
Drug Impaired Driving - Interpretation
1. Driving characteristics
2. Observed signs, behaviors (officer, EMTs, witnesses, others) and performance on field sobriety tests
3. Toxicology report
Are they consistent?
Is the driver impaired?
Texas Penal Code Section 49.01
"Intoxicated" means not having the normal use of mental or physical faculties by reason of the introduction of … a controlled substance, a drug, a dangerous drug, a combination of two or more of those substances, or any other substance into the body….
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DRE & Toxicology80
Drug Recognition Expert (DRE)
DRE performs systematic and standardized tests, observes and documents impairment, and renders opinion
Toxicologist
Provides analytical support, tests samples, provides expert opinion on effects of drugs on human performance
Drug Recognition Evaluation
1. Breath alcohol test2. Interview with arresting officer3. Preliminary examination of suspect4. Examination of the eyes5. Divided attention psychophysical tests6. Vital signs7. Dark room examination8. Muscle tone9. Injection sites10. Suspect’s statements & other observations11. Opinion of evaluator (DRE)12. Toxicological examination
Observations82
Drug Impaired Driving - Interpretation
Texas Penal Code Section 49.01
"Intoxicated" means not having the normal use of mental or physical faculties by reason of the introduction of … a controlled substance, a drug, a dangerous drug, a combination of two or more of those substances, or any other substance into the body….
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Our Role: Test, Interpret, Testify
“I knew the suspect was lying because of certain telltale discrepancies between his voice and nonverbal gestures.
Also, his pants were on fire.”
The ToxicologistAs Expert Witness
W H A T I S A N E X P E R T ?
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Experts Are People Who Know a Great Deal About Very Little,
And Who Go Along Learning More And More About Less And Less
Until They Know Practically
Everything About Nothing
Example: CNS Stimulants87
Central Nervous System (CNS) stimulants E.g. Cocaine, methamphetamine Euphoria Exhilaration Paranoia Impaired motor skills Impaired cognitive functioning Rapid speech, rapid movements, incoherent speech Anxious, excitable Jaw clenching, grinding teeth Muscle tremors, eyelid tremors
CNS Stimulants - DRE88
Pupil size DILATED; reaction to light SLOWED No HGN or VGN Pulse rate ELEVATED Blood pressure ELEVATED Muscle tone rigid Body temperature ELEVATED Injection sites possible
(IV, IN, SM common routes)
89Human Performance Issues
Drive-off-the road accidents
Leaving lane of travel
Speeding
High speed collisions
Erratic or risky driving
Methamphetamine Hysteresis90
Concentration
Effects
ExcitationExhilarationFeel “good”
HyperactiveAgitatedParanoiaConfusionDelusionalIrrationalViolent
FatigueExhaustionConfusionHypersomnolenceDepression
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DUID Case: Hairy Weasel
Driving/Reason for the Stop 30 y male Semi-truck driving erratically Could not maintain lane; officer feared truck may tip
over Traveling southbound in northbound lane Signs/Symptoms/SFSTs While sitting on the curb advised deputy that wheels on
stationary patrol vehicle were moving Driver had seen a weasel run around his truck or it
could have been a hairy little boy about four feet tall Advised of trouble at truck stop where an armed male
and a female had mounted his truck He was driving erratically from side to side to try to
knock off the male, who was brandishing a firearm
DUID Case: Hairy Weasel
Had called animal control to come and get the snakes and weasel from inside his truck
Appeared frantic; Had taken caffeine pills to stay awake OLS – hands and arms in air entire time, poor balance WAT – incorrect number of steps, incorrect turn, nearly fell Good and cooperative attitude Face flushed; rigid muscle tone Unsteady on feet, Eyelid tremors BP 135/90; pulse 112, 130, 106 bpm Pupils 5.5 mm; slow to react Romberg 22s; one inch circular sway Finger to nose - slow and robotic; could not perform testBlood Toxicology Methamphetamine 0.57 mg/L; Amphetamine present
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DUID Case: Zero Motivation
Driving/Reason for the Stop 44 y male Welfare check Officer dispatched to male subject passed out in vehicle
on roadway Vehicle running; truck located at intersection Driver asleep with feet sticking out of drivers side
window in reclined position Truck was in drive, but did not roll due to position on
an inclineSigns/Symptoms/SFSTs Drivers eyes closed but legs were twitching Officer wakes subject; opens eyes, then closes them
again, goes back to sleep
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Officer places vehicle in park, wakes subject When asked for drivers license states “It’s here somewhere” then
laid back in the seat to sleep Says he has been up for days under the influence of drugs Body was twitching, sweating heavily; No HGN When asked to perform FSTs said “ I don’t think I can do them” OLS – Puts foot down more than three times (cannot perform
test); WAT – Steps offline more than three times (cannot perform test)
When asked if he had taken drugs over the past few days said “Sure partner!”
Blood Toxicology Methamphetamine 0.14 mg/L; Amphetamine,
Ephedrine/Pseudoephedrine, Doxylamine, Dextromethorphan present
DUID Case: Zero Motivation
Careers in Forensic Toxicology
B.S. of M.S. Degree in chemistry, biology or related field (entry level)
Ph.D. in toxicology or related field
Medical Examiner’s Offices
Crime Laboratories
Private Sector Drug Testing Laboratories
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Questions???97