by: Nachman Brautbar
"Intoxication, Drugs of Abuse Testing
& Forensics Application
By Nachman Brautbar, M.D.
Recreational use of and abuse of illicit and prescription drugs has grown in the last 15 years, and become a point of concern to both forensic and non-forensic physicians. Various regulatory agencies, insurance companies, and medicolegal processes such as workers compensation and personal injury defense have been utilizing the defense of intoxication (drugs of abuse and alcohol or a combination of either) in order to prove or disprove liability for injury.
Biological Samples for use in Drug Testing
Commonly, three types of biological samples have been utilized: 1. Blood. 2. Urine. 3. Hair. This determines if a patient has used drugs (to strictly determine if the use occurred, as opposed to being under the influence), hair will retain drugs for several months, most commonly 3 months after the use. Urine will retain drugs or their metabolites for anywhere from several hours to several days, or in some rare occasion weeks, and blood will retain the drugs or their metabolites for several hours. Therefore, the use of blood is not relevant to determining whether the patient has used drugs in the past (several days to weeks).
To determine whether the person is impaired as a result of a drug abuse, blood is the best biological tissue to be tested and the most accurate, because the levels in the blood or the presence of the drug in the bloodstream is a very important objective determinant in the process of diagnosing or ruling out the ""impairment or under the influence of drugs or the intoxication defense.
Does Positive Blood Testing, Urine Testing or Hair Testing Indicates Impairment?
Positive hair samples for drugs of abuse does not equate with impairment, it only can determine that in the past a patient has been using drugs (with a given limit). The presence of drugs of abuse in the urine can absolutely not be equated with impairment, but rather use in the last day or several days, and in some extreme cases a week. The presence of drugs or their metabolites in the blood testing does not prove impairment, because there is no scientific data to extrapolate the exact level of illegal drugs that will impair a specific user. That type of extrapolation has been made only for alcohol, which has a legal definition in driving statures, Federal and State, as well as medical forensic extrapolation formulas. (For instance, the blood alcohol disappearance curve.) Commonly a forensic toxicologist and forensic physician will be asked to determine whether urine positivity for illegal drugs indicates that that person was Aunder the influence@ or Aintoxicated@ when an accident occurred on the job, or a car accident occurred on the road. The presence of drugs of abuse or even prescription medication in the urine, or their metabolites in the urine, can not be equated with impairment. Unless clinical data from the site of injury or prior to the injury can indicate that the patient was behaving as an impaired person, even then it will be very difficult to establish impairment. The presence of drugs or their metabolites in the blood may support impairment based on the blood levels and the clinical behavior.
Drug Recognition Expert Program
Due to the problem with identifying impaired workers and driver's in relation to drug blood concentration, the Los Angeles Police Department has developed a program which is called the Drug Recognition Expert Program (DRE). This program started initially with training officers to recognize behavior and psychological status associated with psychoactive drugs, and over the time has attracted the attention of other agencies who were experiencing similar problems. Based on the evaluation the DRE forms an opinion as to: 1. Whether the suspect is impaired. 2. If impaired, whether the impairment is related to drugs. 3. If related to drugs, which drug category or combination of categories is causing the impairment. A recent study (Governor's office of Highway Safety) the police department and DRE program, utilized data software developed by Southern California Research Institute under National Institute on Drug Abuse funding, to record and analyze this data. A patient bank for 390 men and 108 women drivers was analyzed. The DREs correctly identified at least one drug category in 91% of 415 specimens which the laboratory confirmed one or more drugs. No drugs were found in specimens from 26 individuals who the DREs judged not impaired by drugs. The DRE decisions were supported for 83.5% of 484 specimens, and not supported for 16.5 specimens (indicating a significant rate of error).
Related Articles
"Intoxication, Drugs of Abuse Testing
& Forensics Application
By Nachman Brautbar, M.D.
Recreational use of and abuse of illicit and prescription drugs has grown in the last 15 years, and become a point of concern to both forensic and non-forensic physicians. Various regulatory agencies, insurance companies, and medicolegal processes such as workers compensation and personal injury defense have been utilizing the defense of intoxication (drugs of abuse and alcohol or a combination of either) in order to prove or disprove liability for injury.
Biological Samples for use in Drug Testing
Commonly, three types of biological samples have been utilized: 1. Blood. 2. Urine. 3. Hair. This determines if a patient has used drugs (to strictly determine if the use occurred, as opposed to being under the influence), hair will retain drugs for several months, most commonly 3 months after the use. Urine will retain drugs or their metabolites for anywhere from several hours to several days, or in some rare occasion weeks, and blood will retain the drugs or their metabolites for several hours. Therefore, the use of blood is not relevant to determining whether the patient has used drugs in the past (several days to weeks).
To determine whether the person is impaired as a result of a drug abuse, blood is the best biological tissue to be tested and the most accurate, because the levels in the blood or the presence of the drug in the bloodstream is a very important objective determinant in the process of diagnosing or ruling out the ""impairment or under the influence of drugs or the intoxication defense.
Does Positive Blood Testing, Urine Testing or Hair Testing Indicates Impairment?
Positive hair samples for drugs of abuse does not equate with impairment, it only can determine that in the past a patient has been using drugs (with a given limit). The presence of drugs of abuse in the urine can absolutely not be equated with impairment, but rather use in the last day or several days, and in some extreme cases a week. The presence of drugs or their metabolites in the blood testing does not prove impairment, because there is no scientific data to extrapolate the exact level of illegal drugs that will impair a specific user. That type of extrapolation has been made only for alcohol, which has a legal definition in driving statures, Federal and State, as well as medical forensic extrapolation formulas. (For instance, the blood alcohol disappearance curve.) Commonly a forensic toxicologist and forensic physician will be asked to determine whether urine positivity for illegal drugs indicates that that person was Aunder the influence@ or Aintoxicated@ when an accident occurred on the job, or a car accident occurred on the road. The presence of drugs of abuse or even prescription medication in the urine, or their metabolites in the urine, can not be equated with impairment. Unless clinical data from the site of injury or prior to the injury can indicate that the patient was behaving as an impaired person, even then it will be very difficult to establish impairment. The presence of drugs or their metabolites in the blood may support impairment based on the blood levels and the clinical behavior.
Drug Recognition Expert Program
Due to the problem with identifying impaired workers and driver's in relation to drug blood concentration, the Los Angeles Police Department has developed a program which is called the Drug Recognition Expert Program (DRE). This program started initially with training officers to recognize behavior and psychological status associated with psychoactive drugs, and over the time has attracted the attention of other agencies who were experiencing similar problems. Based on the evaluation the DRE forms an opinion as to: 1. Whether the suspect is impaired. 2. If impaired, whether the impairment is related to drugs. 3. If related to drugs, which drug category or combination of categories is causing the impairment. A recent study (Governor's office of Highway Safety) the police department and DRE program, utilized data software developed by Southern California Research Institute under National Institute on Drug Abuse funding, to record and analyze this data. A patient bank for 390 men and 108 women drivers was analyzed. The DREs correctly identified at least one drug category in 91% of 415 specimens which the laboratory confirmed one or more drugs. No drugs were found in specimens from 26 individuals who the DREs judged not impaired by drugs. The DRE decisions were supported for 83.5% of 484 specimens, and not supported for 16.5 specimens (indicating a significant rate of error).
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