With forensic evidence, and in particular toxicological testing results, often dominating criminal trials and probation violation hearings, a Massachusetts criminal defense lawyer must possess an intimate understanding of the strengths and weaknesses of various forensic techniques and disciplines to adequately represent his clients during these critical stages of these criminal proceedings. Too many Boston criminal defense lawyers fail to challenge the government’s toxicology evidence, mostly because they overestimate its reliability or are unsettled by matching wits with the government’s forensic expert. As discussed below, failing to contest toxicology evidence can lead to convictions of innocent men and women, as well as imprisonment for those who are unfairly found to have violated probation for a “dirty” toxicology screen result.
Toxicology Basics
Toxicology is the study of poisons, toxins, and toxicants and how they affect living organisms. Toxicants are toxic chemicals produced by plants or animals. Poison is a toxicant that causes death or illness when digested, inhaled or absorbed through the skin or mucous membrane.
With the advancement of science, we are able to better understand how different chemicals affect us, right down to the molecular level. It was commonly accepted that most chemicals could be consumed in moderation without causing significant damage. Today’s toxicologists no longer believe that is true.
Through testing, toxicologists determine the median lethal dose (LD50) of a toxin, radiation, pathogen, or dose. The LD50 is, essentially, an expression of the lethality of a toxin, etc.; the quantity of a toxin that would prove fatal to 50% of a tested population during a pre-determined testing period. Toxicologists may also refer to LD50 as a semi-lethal dose, though the definition of semi-lethal dose is less precise.
The dose-response relationship examines how the reaction changes when the dose is increased, and specifically at what point the substance becomes a poison. For example, if a person consumes more than the prescribed dosage of a medication, such as a post surgery painkiller, the medication may prove more harmful than helpful. Indeed, if the patient exceeds the recommended dosage or the poisonous threshold, he is at risk of overdosing, suffering irreversible brain or liver damage, or even death.
The path the chemical takes when ingested will determine how it affects the body. Other factors include the species, age, size, health, length of exposure to the chemical, the chemical involved, and the exact amount and concentration of that chemical. A chemical may be lethal as one large dose at once, or it may be lethal or harmful if consumed in smaller doses over a lengthier period of time.
Autopsy: Identifying Toxins & Intoxicants
When a Massachusetts medical examiner conducts an autopsy, he not only is responsible for determining the cause of death, but also for ruling out other possible causes of death, such as an overdose, poisoning, or a lethal combination of otherwise lawful drugs. Therefore, he may take biological samples from the deceased, including saliva, blood, hair, urine, liver, and stomach contents for toxicological testing and test the same for toxins, toxicants, or poisons. From this testing, the toxicologist and/or the medical examiner may be able to determine not only the cause of death, but whether the deceased had consumed drugs or alcohol, and in what quantities, prior to his death. Post mortem testing can, however, be highly unreliable because the results do not mirror the drug concentrations at the time of death. Indeed, the concentration of a drug in an autopsy blood sample may be quite higher by a factor of several-fold, depending to a great degree on how much time elapsed, following death, before the biological sample was obtained and the age of that sample at the time of the testing. There is, therefore, a real danger that in individuals taking therapeutic doses of a drug, an artificially elevated post mortem drug level may be misinterpreted as a lethal overdose.
Toxicology results may also assist the defense. A Massachusetts criminal defense attorney can use the presence of alcohol or illegal drugs in the deceased’s system to show that, just prior to his death, he was behaving in a bizarre and hyper-aggressive manner, to corroborate his client’s claim that he inflicted the fatal wound in self-defense. Where our client was charged with motor vehicle homicide, we were able to use the toxicology results showing the deceased was under the influence of drugs to discredit the government’s theory that our client was at fault. That client was acquitted.
Rape Kit
If an individual claiming to have been sexually assaulted submits to a Rape Kit, Massachusetts hospital staff will normally take a sample of her blood. Toxicological testing of the blood may establish that she was intoxicated, even perhaps too intoxicated to consent to sexual relations, or had been slipped a so-called “date rape” drug. The presence of a “date rape” drug can be powerful evidence in the hands of an experienced prosecutor. Conversely, the absence of a “date rape” drug or intoxicating level of alcohol or drugs may prove critical to the defense’s attempts to discredit the alleged victim.
Toxicology Tests
A toxicological test is designed to detect one or more drugs or chemicals present in blood or urine. Drug tests are, essentially, divided into two groups: screening tests and confirmatory tests.
Screening Tests
Massachusetts probation officers, as well as clinics providing random drug testing, use relatively inexpensive screening tests to detect the presence of drugs/chemicals. Screening tests can detect as many as 30 different drugs/chemicals, provide rapid results, and require no laboratory or sophisticated toxicological equipment. Screening tests are usually limited to detecting the target drugs/chemicals in fresh urine, rather than blood, saliva or other bodily fluids. Most screening tests are immunoassays, typically radioimmunoassays (RIA).
Immunoassays do not, actually, identify the targeted drugs/chemicals. Instead, because these tests rely on competitive binding, they identify only antigen-antibody reactions, with the targeted drug acting as the antigen. When the drug is present in the sample, the antigen-linked drug is not bound to the antibody and is free to react with other substances in the testing solution. The antigen-antibody complex is precipitated out of the solution, and the proportion of antibody bound to labeled versus unlabeled antigen (drug) is quantified. Immunoassay tests are often highly sensitive, meaning they will detect vanishingly small amounts of the targeted drugs. Though sensitive, these tests are notoriously unreliable. False positives are not uncommon in immunoassay testing because the antigen may bind to a similarly structured chemical. For these reasons, many courts will not admit unconfirmed immunoassay testing results at trials. Unfortunately, probation officers and courts continue to violate probationers based on the results of dubious immunoassay testing results.
Confirmatory Testing
Because of the inherent unreliability of screening tests, the presence of the targeted drug/chemical should be confirmed with sophisticated laboratory equipment that is both sufficiently sensitive and highly reliable. It is not enough to “confirm” one screening test with another, though different, screening test.
Gas Chromatography-Mass Spectrometry
Gas Chromatography-Mass Spectrometry is widely regarded as an ideal confirmatory test, both because of its sensitivity (it will detect extremely small trace amounts of the targeted drug/chemical) and reliability (it will not misidentify a drug/chemical). In GC/MS, a chemist prepares the sample for testing and then places it within the instrument. Initially, the sample is analyzed by the gas-chromatograph, which converts the sample into its gaseous form and pushes it through a long glass column with helium gas. Each individual chemical emerges from the glass column at a specific time, measured in hundredths of a second. From this simple measurement, toxicologists and chemists can identify drug or chemical. There is, however, as second portion of the GC/MS test: as the drug exits, it is bombarded by electrons, breaking it into pieces that are then analyzed by a mass spectrometer. Under proper conditions, a drug/chemical will always break up into the same parts, allowing the mass spectrometer identify the drug/chemical by the weights and relative amounts of the various pieces. This two-pronged test, which identifies the precise time when a particular drugs exits from the column and identifies the characteristic molecular “fingerprint” of a particular drug by scrutinizing its component parts, is considered extremely reliable by the scientific community.
Detection Durations
Typical screening tests utilized by probation officers and clinics can detect targeted drugs for various periods of time following the last usage, depending on the particular drug, dosage, frequency of use, period of time over which the drug has been used, as well as the individual’s metabolic rate, body mass, age, and overall health. The detection duration depends to a considerable extent on the sample tested, whether hair, urine or blood. Below, please find the durations times of the following drugs/chemicals:
In Urine:
- Alcohol: 3-10 hours
- Amphetamines: 1-2 days
- Barbiturates: 6 weeks
- Benzodiazepines: 6 weeks
- Cocaine/Cocaine Metabolites: 2-4 days (10-22 days with heavy use)
- Codeine: 1-2 days
- Heroin/Opiates: 1-2 days
- LSD: 2-24 hours
- Methamphetamines: 1-2 days
- Methadone: 2-3 days
- Morphine: 1-2 days
- Phencyclidine (PCP): 1-8 days
- Propoxyphene: 6-48 hours
- Cannibis/Tetrahydrocannabinol (THC): 6-11 (weeks with heavy use)
In Blood:
- Alcohol: 12 or more hours
- Amphetamines: 12 hours
- Barbiturates: 6 weeks
- Benzodiazepines: 6 weeks
- Cocaine/Cocaine Metabolites: 2-4 days (10-22 days with heavy use)
- Codeine: 1-2 days
- Heroin/Opiates: 1-2 days
- LSD: 2-24 hours
- Methadone: 2-3 days
- Methamphetamines: 12 hours
- Morphine: 1-2 days
- Phencyclidine (PCP): 1-8 days
- Propoxyphene: 6-48 hours
- Cannibis/Tetrahydrocannabinol (THC): 6- 11 weeks with heavy use
In Hair:
- Alcohol: detectable 1 week following consumption and up to 6 months
- Amphetamines: up to 90 days
- Barbiturates: unknown
- Benzodiazepines: unknown
- Cocaine/Cocaine Metabolites: up to 90 days
- Codeine: up to 90 days
- Heroin/Opiates: up to 90 days
- LSD: 3-4 days
- Methamphetamines: up to 90 days
- Methadone: more than 100 days
- Morphine: up to 90 days
- Phencyclidine (PCP): up to 90 days
- Propoxyphene: unknown
- Cannibis/Tetrahydrocannabinol (THC): up to 90 days
Our Greatest Success
With the assistance of a forensic toxicologist, Massachusetts criminal defense attorney Kevin J. Mahoney freed Christina Martin, who had been unjustly convicted of 1st degree murder. By doing what her former lawyer had failed to do – successfully challenging the reliability of the screening tests performed by the Massachusetts State Police Crime Laboratory and unearthing confirmatory testing results that contradicted the screening tests – convinced a Massachusetts Superior Court judge to overturn her conviction.
Contact Us
If you or a loved one is in need of a Massachusetts Criminal Defense Lawyer, kindly call us at 617-492-0055 to arrange an in-office consultation with Attorney Mahoney.
