Forensic Toxicology & Drug Katherine Sato Office of the Ohio Public Chemistry for Defense Attorneys Defender
Introduction Forensic Toxicology Outline of Alcohol/OVI Testing Presentation Drug Field Testing Drug Chemistry for the Defense
Forensic Chemistry Forensic Toxicology Various Fields May Pharmacology Apply Pharmacogenetics and Pharmacokinetics
Forensic Chemistry The application of analytical techniques in a legal setting for the purpose of identification of unknown chemical substances
Forensic Toxicology Employs the analytical techniques of chemistry for the detection of drugs, toxins, and/or pharmaceuticals in biological samples
Pharmacology Both the overt effects of biologically active chemicals and the mechanism by which these chemicals interact with each other and biological targets
Pharmacokinetics
Pharmacogenetics
Expert Testimony
Cross-discipline fields → may need multiple experts Who Can May need to circumscribe an Testify? expert’s testimony Right to confrontation
Melendez-Diaz v. Massachusetts (2009) SCOTUS: defendants have a right to confront laboratory analysts Held: 1. Analysts’ certificates of analysis are testimonial statements; 2. Analysts are not removed from coverage of Confrontation Clause 3. Defendant’s ability to subpoena analyst did not obviate State’s obligation to produce analyst for cross-examination
Melendez-Diaz v. Massachusetts (2009) “Nor is it evident that what respondent calls ‘neutral scientific testing’ is as neutral or as reliable as respondent suggests. Forensic evidence is not uniquely immune from the risk of manipulation. According to a recent study conducted under the auspices of the National Academy of Sciences, ‘[t]he majority of [laboratories producing forensic evidence] are administered by law enforcement agencies, such as police departments, where the laboratory administrator reports to the head of the agency.’ * * * And ‘[b] ecause forensic scientists often are driven in their work by a need to answer a particular question related to the issues of a particular case, they sometimes face pressure to sacrifice appropriate methodology for the sake of expediency.’ A forensic analyst responding to a request from a law enforcement official may feel pressure — or have an incentive — to alter the evidence in a manner favorable to the prosecution.”
R.C. 2925.51 In any criminal prosecution, a laboratory report from BCI (or other accredited lab) stating: 1. That the substance has been weighed and analyzed; 2. The findings as to the content, weight, and identity of the substance; 3. That it contains any amount of a controlled substance; and 4. The number and description of unit dosages Is “prima facie evidence” of the content, identity, and weight of the substance.
State v. Pasqualone (OSC 2009) When the state has complied with its obligations under R.C. 2925.51, a defendant’s failure to use the procedures of R.C. 2925.51(C) to demand that a laboratory analyst testify constitutes a waiver of the opportunity to cross-examine the analyst at trial and allows the analyst’s report to be admitted as prima facie evidence of the test results.
Bullcoming v. New Mexico (2011) “We hold that surrogate testimony * * * does not meet the constitutional requirement. The accused’s right is to be confronted with the analyst who made the certification, unless that analyst is unavailable at trial, and the accused had an opportunity, pretrial, to cross-examine that particular scientist.” “SLD analysts use gas chromatograph machines to determine BAC levels. Operation of the machines requires specialized knowledge and training. Several steps are involved in the gas chromatograph process, and human error can occur at each step.”
“Drug Recognition Experts” • Made up field/ mostly nonscientists • One week-long training and they claim to identify whether a person was on PCP vs. heroin • Challenge on scientific basis for their observations • Do not have knowledge of how drugs affect the human body
Forensic Toxicology
Metabolism • The whole range of biochemical processes that occur within a living organism • Consists of anabolism (the buildup of substances) and catabolism (the breakdown of substances)
Metabolism • Enzymes convert drugs into metabolites • Metabolites may be therapeutic, harmful, or inactive • Cannot use metabolites as indicator of impairment (not psychoactive) • May need expert in pharmacokinetics (to determine how quickly individual metabolizes specific drug) if when the person took the drug is important
Half-Life
Metabolism of Cocaine
Blood Urine Can determine impairment Cannot determine impairment Varies less by individuals Individual variation More invasive Less invasive, more common Blood vs. Urine Detection
Post-Collection Changes • If a toxin is in the urine, it will stay there if properly stored • Not going to continue breaking down • Some exceptions (e.g., if someone has a lot of sugar and yeast in the urine, could change to alcohol after it leaves the body while stored)
AG’s Guidelines
Hair Testing • As someone is exposed to drugs, the actively growing hair will sequester some of the drug • Once drugs deposited in hair shaft, remains part of hair indefinitely • Drugs are deposited in the root and then continue down the hair as it grows • Normally collect about 3 cm
Alcohol/OVI Testing
Standardized field sobriety tests Types of OVI Field Tests Intoxilyzers
Standardized Field Sobriety Tests Three tests used in combination to determine intoxication: 1. Horizontal Gaze Nystagmus (HGN) – involuntary eye movement 2. Walk-and-Turn (WAT) – divided attention activity 3. One-Legged Stand – divided attention activity Should only be used for alcohol, not proper for marijuana or any other drugs
National Highway Traffic Safety Administration (NHTSA) found that, in determining whether a subject’s BAC was .10 or above: Reliability of • The HGN by itself was 77% accurate • The Walk-and-Turn by itself was 68% Standardized accurate Field Sobriety • The One-Leg Stand by itself was 65% accurate Tests • The HGN and WAT in combination were 80% accurate One study found 24% false positive results
Intoxilyzers • Device that measures ethanol expelled from the lungs • Used alone or with SFSTs • Blood alcohol concentration (BAC) is then estimated from breath alcohol concentration (BrAC) using a generalized ratio of BAC:BrAC = 2100:1 • Can vary by individuals • No evidence this specific equation applies to your client • Range in calculation could be the difference between BAC of .079 and .08 • Requires 15- to 20-minute waiting period
Assumes partition ratio of 2100:1 One breath sample Intoxilyzers: Calibration Potential Errors Temperature Non-selective Sample destroyed
Discovery Request for Intoxilyzers Calibration All solutions used to information calibrate the machine Margin of error of all Maintenance of the solutions used to instrument calibrate the machine
R.C. 4511.19(D)(1)(b) • “In any criminal prosecution or juvenile court proceeding for [OVI], the court may admit evidence on the concentration of alcohol * * * in the defendant’s * * * breath * * * at the time of the alleged violation as shown by chemical analysis of the substance withdrawn within three hours of the time of the alleged violation.” • “The bodily substance withdrawn under division (D)(1)(b) of this section shall be analyzed in accordance with methods approved by the director of health * * *”
State v. Vega (OSC 1984) Because the legislature provided for the admissibility of intoxilyzer tests if analyzed in accordance with methods approved by the director of ODH, an accused may not present expert testimony attacking the general scientific reliability of approved test instruments.
Cincinnati v. Ilg (OSC 2014) The approval of a breath-analyzer machine by the director of the Ohio Department of Health does not preclude an accused from challenging the accuracy, competence, admissibility, relevance, authenticity, or credibility of a specific test result or whether the specific machine used to test the accused operated properly at the time of the test.
Retrograde Extrapolation Can someone reliably estimate the amount of alcohol ingested from a single measurement of a person’s blood alcohol concentration (BAC)?
Blood-Alcohol Curve
Widmark Formula
People v. Floyd (IL 2014) “A retrograde extrapolation calculation based on a single breath test, and when many of the factors necessary to determine whether the defendant was in the elimination phase are unknown, is insufficient to provide a reliable calculation and invites the jury to determine guilt on an improper basis. Based on the specific circumstances presented in this case, we believe that the prejudicial effect of the retrograde extrapolation calculation substantially outweighed its probative value and that the trial court abused its discretion in admitting it.”
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