Transcript Forensic Toxicology - UCO

Forensic Toxicology
Analytical Toxicology
Fall 2007
Forensic Toxicology
Toxicology is defined as the
study of the adverse effects of
chemicals on living organisms.
Forensic toxicology is defined
as the application of toxicology
for the purposes of the law.
Forensic Toxicology
Postmortem forensic
toxicology.
Human performance
toxicology.
Forensic drug testing.
History
Ancient Egyptians and Grecians
reported poisonings due to herbs,
plants and food.
Opium, arsenic and hydrocyanic
acid were used throughout
Europe during the middle ages.
History
 Philippus Theophrastus Aureolus
Bombastus von Hohenheim (or
Paracelsus) observed that any
substance could be a poison,
depending on its dose
 “ What is there that is not poison? All
things are poison and nothing without
poison. Solely the dose determines
that a thing is not a poison”
History
 In 1814, M.J.B. Orfila, the
chairman of the legal medicine
department at the Sorbonne in
France, published a book entitled
Traite des poisons ou Toxicologie
Generale.
History
 In 1851, Stas developed the first
effective method for extracting
alkaloids from biological
specimens.
 This was modified several years
later by Otto, which enabled the
isolation of purer alkaloid
substances.
History
 In the U.S., forensic toxicology did
not develop until the early 20th
century.
 Dr. Alexander Gettler is considered
this country’s first forensic
toxicologist.
Postmortem Forensic
Toxicology
 Suspected drug intoxication cases
 Homicides
 Arson fire deaths
 Motor vehicle fatalities
 Deaths due to natural causes
Postmortem Forensic
Toxicology
 Death Investigations
 Coroner
 Medical Examiner
Postmortem Forensic
Toxicology
 Specimens
 Blood – from the heart and from the
femoral or jugular veins
 Vitreous humor
 Urine
 Bile
 Liver
 Other – lung, spleen, stomach contents
or brain
Postmortem Forensic
Toxicology
 Analytical Process
 Separation
 Identification
 Confirmation
 Quantitation
Postmortem Forensic
Toxicology
 Analytes
 Volatiles (Carbon Monoxide,
Cyanide, and Alcohols)
 Drugs
 Metals
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EHTANOL (1.787 min.)
MEK(ISTD) (5.584 min.)
ACETONE (2.462 min.)
2-PROPANOL (2.804 min.)
ACETALDEHYDE (1.414 min.)
Postmortem Forensic
Toxicology
 Drugs
 One Comprehensive Approach:
Postmortem Forensic
Toxicology
 Metals
 Aluminum
 Arsenic
 Iron
 Mercury
 Lead
 Thallium
Postmortem Forensic
Toxicology
 Metals (continued)
 Analysis
Colorimetric
Graphite Furnace Atomic Absorption
Spectrometry
Inductively Coupled Plasma – Mass
Spectrometry
Neutron Activation Spectrometry
Human Performance
Toxicology
 Human performance toxicology is
also referred to as behavioral
toxicology.
 It is the study of human
performance under the influence of
drugs.
Human Performance
Toxicology
 Ethanol and driving
 History
 Behavioral effects
 Specimens
Ethanol Toxicology
 Types of alcohol
 Ethanol (ethyl alcohol)
 Methanol (methyl alcohol)
 Isopropanol
 Ethylene glycol
Ethanol Toxicology
 Ethanol production
 Fermentation of sugar or starch
Can only achieve 20% ethanol
 Distillation
Distilled alcoholic beverages are usually
40 to 50% ethanol by volume (80-100
proof)
Ethanol Pharmacokinetics
 Absorption
 Means of absorption
Dermal
Inhalation
IV
Oral
 Gastrointestinal tract
 Presence of food.
Ethanol Pharmacokinetics
 Distribution
 Gastrointestinal tract
 Portal vein
 Liver
 Heart
 Lung
 Heart
 Body
Ethanol Pharmacokinetics
 Elimination
 5-10% in the urine
 Saliva, expired air and sweat
 Liver (enzymatic oxidation to
acetaldehyde, acetic acid and carbon
dioxide)
Ethanol Effects on the Body
 Cardiovascular system
 Central nervous system
 Gastrointestinal tract
Ethanol Effects on the Body
 Kidney
 Liver
Breath Ethanol Testing
 Theory
 Henry’s law
 Ethanol in breath Vs ethanol in blood
2100 to 1 ratio
2300 to 1 ratio
Breath Ethanol Testing
 Types of analyzers
 Chemical
Reaction of ethanol with potassium
dichromate/sulfuric acid solution
Colored solution that results is measured
spectrophotometrically
 IR spectrophotometry
 Electrochemical oxidation - fuel cell
Breath Ethanol Testing
 IR Spectrophotometry
 Based on absorbance of light by the
ethanol molecule
 Mainstay in evidential breath testing
devices
 Electrochemical Oxidation
 Oxidation of ethanol to acetic acid
 Also used in evidential breath testing
Blood Ethanol Testing
 Chemical
 Screening
 Quantitative
 Disadvantage - aldehydes and ketones
will interfere with the test
Blood Ethanol Testing
 Enzymatic
 Conversion of NAD to NADH by
ethanol (serum, urine and whole
blood)
Measured spectrophotometrically at
340 nm
 Same reaction with a blue dye
(thiazoyl blue) (serum, urine, fresh
blood and postmortem blood)
Measured with a fluorometer
 Gas Chromatography
MEK(ISTD) (5.584 min.)
ACETONE (2.462 min.)
2-PROPANOL (2.804 min.)
ACETALDEHYDE (1.414 min.)
EHTANOL (1.787 min.)
Blood Ethanol Testing
 Can measure ethanol in a wide range
of specimens
 Can distinguish ethanol from other
alcohols, aldehydes and ketones
 Two common methods
Head space
Direct injection
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Assessment of Ethanol
Impairment
 In a British study:
 Detectable deterioration of drivers at
between 30 – 50 mg/dL
 Obvious deterioration observed at between
60 – 100 mg/dL
 In another British study:
 Pilots exhibited impairment at 40 mg/dL
Assessment of Ethanol
Impairment
 Blood alcohol concentration:
 10-50 mg/dL: Impairment detectable
by special tests
 30-120 mg/dL: Beginning of
sensory-motor impairment
 90-250 mg/dL: Sensory-motor
incoordination; impaired balance
 180-400 mg/dL: Increased muscular
incoordination; apathy; lethargy
Assessment of Ethanol
Impairment
 Blood alcohol concentration:
 250-400 mg/dL: Impaired
consciousness; sleep; stupor
 350-500 mg/dL: Complete
unconsciousness; coma
 450 and greater mg/dL: Death from
respiratory arrest
Stages of Acute Alcohol Intoxication*
Blood-Alcohol
Concentration
g/ 100mL
0.01-0.05
Stage of
Alcoholic
Influence
Sub clinical
Clinical Signs/ Symptoms
Influence/ effects not apparent or obvious
Behavior nearly normal by ordinary observation
Impairment detectable by special tests
0.03-0.12
Euphoria
Mild euphoria, sociability, talkativeness
Increased self-confidence; decreased inhibitions
Diminution of attention, judgment, and control
Beginning of sensory-motor impairment
Slowed information processing
Loss of efficiency in critical performance tests
0.09-0.25
Excitement
Emotional instability; loss of critical judgment
Impairment of perception, memory, and comprehension
Decreased sensory response; increased reaction time
Reduced visual acuity, peripheral vision, and glare
recovery
Sensory-motor incoordination; impaired balance
Drowsiness
0.18-0.30
Confusion
Disorientation, mental confusion; dizziness
Exaggerated emotional states (fear, rage, grief, etc.)
Disturbances of vision (diplopia, etc.) and of perception of
color, form, motion, dimensions
Increased pain threshold
Increased muscular incoordination; staggering gait; slurred
speech
Apathy, lethargy
0.25-0.40
Stupor
General inertia; approaching loss of motor functions
Markedly decreased response to stimuli
Marked muscular incoordination; inability to stand or walk
Vomiting; incontinence of urine and feces
Impaired consciousness; sleep or stupor
0.35-0.50
Coma
Complete unconsciousness; coma; anesthesia
Depressed or abolished reflexes
Subnormal temperature
Impairment of circulation and respiration
Possible death
0.45+
Death
Death from respiratory arrest
*Reprinted by permission of K.M. Dubowski, 1997.
Human Performance
Toxicology
 Drugs and driving
 DEC program
Drug recognition expert
Toxicologist
Prosecution
Human Performance
Toxicology
 Drug Recognition Evaluation - 12
Step Process
 Breath alcohol test
 Interview of the arresting officer.
 Preliminary examination of the suspect.
 Examination of the eyes.
 Divided attention psychophysical tests.
 Vital signs examination.
Human Performance
Toxicology
 Drug Recognition Evaluation
(continued)
 Dark room examination.
 Examination of muscle tone.
 Examination for injection sites.
 Suspect’s statements and other
observations.
 Opinion of the evaluator.
 Toxicological examination.
Human Performance
Toxicology
 Drug Recognition Evaluation
Human Performance
Toxicology
Drug Recognition Evaluation
Human Performance
Toxicology
 Drug Recognition Evaluation
(continued)
 Toxicology
Type of Testing
Specimens
Human Performance
Toxicology
 Drug Recognition Evaluation
(continued)
 Drug Class Effects
Central Nervous System Depressants
Central Nervous System Stimulants
Hallucinogens
Phencyclidine
Narcotic Analgesics
Inhalants
Cannabis
Forensic Drug Testing
 Introduction
 History
 Military
 Criminal justice system
 Public sector
 Private sector
 Rationale
Forensic Drug Testing
 Uses in the workplace:
 Pre-employment screening
 Post-accident testing
 Return to Work testing
 “For Cause” testing
 Random testing
Forensic Drug Testing
Military Experience
Forensic Drug Testing
President Ronald Reagan
1986
Executive Order No. 12564
Objective: To develop a
“drug-free” workplace.
Forensic Drug Testing
Mandatory Guidelines
for Federal
Workplace
Drug Testing
Programs
Forensic Drug Testing
Mandatory Guidelines
Laboratory Accreditation
Specified Menu & Cutoffs
 Proficiency Testing
Inspections
External Blind Controls
Corrective Actions
Forensic Drug Testing
Programs:
Federal Dept. of Health & Human
Services (DHHS)
National Institute on Drug Abuse (NIDA)
Substance Abuse & Mental Health
Services Administration (SAMHSA)
Forensic Drug Testing
Programs:
Department of Transportation
(DOT)
Nuclear Regulatory Commission
(NRC)
College of American Pathologists
(CAP)
Forensic Urine Drug Testing (FUDT)
Forensic Drug Testing
Specimen Collection
External Custody & Control Form
Unobserved/Observed Collection
Toilet Water (Off or Blue)
Sink Water (Off or Cold)
No purses or bags
No large coats
Minimum Volume
Check Temperature
Split specimen
Specimen Bottle Seal
Forensic Drug Testing
Standard
Operating
Procedures
SOP
Forensic Drug Testing
Test Menus – SAMHSA
Screen for Drugs:
Amphetamines
Cannabinoids
Cocaine Metabolite
Opiates
Phencyclidine
(Alcohol)
Forensic Drug Testing
Test Menus – SAMHSA
Drugs Confirmed:
Amphetamine, Methamphetamine
Delta-9-Tetrahydrocannabinol Carboxylic
Acid (THCA)
Benzoylecgonine
Codeine, Morphine, 6-Acetylmorphine
Phencyclidine
(Alcohol)
Forensic Drug Testing
Test Menus – SAMHSA
Specimen Validity:
Temperature
pH
Creatinine
Specific Gravity
Nitrite
Pyridine, Glutaraldehyde, Bleach,
Soap, Chromium
Forensic Drug Testing
Test Menus – CAP & non-DOT
Drugs:
“NIDA-5”
plus
Barbiturates, benzodiazepines,
methadone, propoxyphene
MDA, MDMA
Others?
Forensic Drug Testing
Test Menus – CAP
Validity:
Same as SAMHSA
Forensic Drug Testing
Test Procedures
SAMHSA / DOT
Screening: Immunoassay (Emit, RIA,
FPIA, CEDIA)
Confirmation: GC/MS
Alcohol: Alcohol Screening Device
Evidential Breath Tester
GC
Forensic Drug Testing
Test Procedures
CAP & Non-DOT
Screening: Immunoassay (Emit, RIA,
FPIA, CEDIA)
Automated Clinical Analyzer (EtOH)
Alcohol: Alcohol Screening Device
Confirmation: GC, GC/MS
Alcohol: Evidential Breath Tester
GC
Forensic Drug Testing
Cutoff Concentration
That concentration below which the
analytical result must be reported as
“Negative”
A cutoff concentration is specified for
screening analysis and for
confirmation analysis for each
analyte.
Forensic Drug Testing
Cutoff Concentrations (ng/mL)
Phencyclidine
Screening 25
Confirmation 25
Forensic Drug Testing
Cutoff Concentrations (ng/mL)
Screening
Cocaine metabolites 300
Confirmation
Benzoylecgonine 150
Forensic Drug Testing
Cutoff Concentrations (ng/mL)
Screening
Marijuana metabolites 50
Confirmation
Delta-9-THCA 15
Forensic Drug Testing
Cutoff Concentrations (ng/mL)
Screening
Amphetamines 1000
Confirmation
Amphetamine 500
Methamphetamine 500
(and Amphetamine 200)
Forensic Drug Testing
Cutoff Concentrations (ng/mL)
Screening
Opiates 2000
Confirmation
Codeine 2000
Morphine 2000
(Test for 6-AM 10)
Forensic Drug Testing
Security of
Laboratory
Facility
Forensic Drug Testing
Chain of Custody
External Custody and
Control Form
Internal Chain of
Custody Forms
(Specimen and aliquots)
Forensic Drug Testing
Specimen Storage
Refrigerated while analyses in
process;
Discarded if negative;
Frozen ( -20 o C) > 1 year if
positive.
Forensic Drug Testing
Validation of:
Methods
Instruments
Reagents
Forensic Drug Testing
Reporting Results
“Negative” if either screening or
confirmation gives negative result.
“Positive” only if positive result for
both screening and confirmation.
“Test Not Performed”
Forensic Drug Testing
Reporting Results
Rejected for Testing
(Give Remark)
Fatal Flaw
Uncorrected Flaw
Specimen Unsuitable
Specimen Adulterated
Specimen Substituted
Forensic Drug Testing
Reporting Results
If specimen donor requests, “split”
specimen may be sent to another
certified laboratory to retest for that
substance reported positive.
Forensic Drug Testing
Quality Control /
Quality Assurance
Screening Quality Control
Confirmation Quality Control
Proficiency Testing
Forensic Drug Testing
Screening Quality Control
Calibrator / Cutoff
Controls:
Open - Blank, Negative, Positive,
Blinds (external and internal)
Forensic Drug Testing
Confirmation Quality Control
Calibrators:
Single vs. Multiple point
Controls:
Open - Blank, Negative, Positive,
Blinds (external and internal)
Carryover
Forensic Drug Testing
Proficiency Tests
Samples submitted by an outside
agency.
May be negative;
May be positive.
Forensic Drug Testing
Proficiency Tests
No false positives
Identify 90% of drug challenges
Quaititate 80% within +/- 20% or +/2 SD of target value.
Forensic Drug Testing
Inspections
Semi-Annual
Number of Inspectors &
Number of Days
Depends on size of laboratory
Review SOP, talk to staff, watch sample
processing, look at lots of case records,
personnel records, proficiency test records,
security records, instrument logs, etc., etc., etc.
Forensic Drug Testing
Personnel
New Titles:
Responsible Person (RP)
Certifying Scientist
Medical Review Officer (MRO)
Collector
Accessioner
Records Custodian