Intoxication,Drugs of abuse testing & forensics A

[DADOCTOR]

November 6, 2008



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.

Biological Samples for use in Drug Testing
Commonly, three types of biological samples have been utilized: 1. Blood. 2. Urine. 3. Hair. 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 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. 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.



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). 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. 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. A marijuana positive in urine which is not supported with evidence of behavioral impairment, cannot and does not speak to the question of drug Aintoxication@.

The presence of drugs of abuse in the blood cannot automatically be extrapolated to the Aintoxication defense.

Medications and Substances Causing False Positives
There are 161 prescription and over-the-counter medications which have been studied and show that 65 of them produce false positive results in the commonly administered urine test for drugs. The next epidemic will be testing abuse.”" The most commonly used urine testing methodology is AMIV, has been shown that over 250 over-the-counter medications and prescription drug interactions can cause false positive testing using this methodology. All drugs containing Ibuprofen.



Methodology of Drug Screening in Urine
There are several methods to detect drugs in the urine. The only accepted procedures based on the definition of the National Institute of Drug Abuse (NIDA), and the Department of Defense (DOD), are immunoassays followed by gas chromatography/mass spectrometry confirmation. The confirmation utilizing gas chromatography/mass spectrometry is required since the methodology of immunoassay can give false positive results due to cross reactivity.



Forensic Accuracy of GS/MS
Gas chromatography/mass spectrometry is extremely and highly accurate if done correctly.



Drug of Abuse and Hair Testing
Hair testing for drug of abuse testing has become extremely popular among employers. For example, the Society of Forensic Toxicologists in 1990 stated: “”The use of hair analysis for employees in pre-employment drug testing is premature, and cannot be supported by the current information on hair analysis for drugs of abuse.”" At the emergency room urine was sent to the lab for drug screening. Upon recovery from the injury the patient requested Workers Compensation benefits, and was denied since the urine drug screening utilizing EMIT methodology (immunological) detected opiates.



In his deposition the patient testified that he has never used drugs, did not use drugs on the date of injury either. The physician who examined the patient on behalf of the insurance carrier failed to note the time of the testing, the time the urine was obtained from the patient, whether the patient was taking any medications which contain amphetamines, such as ephedrines or pseudoephedrines.



The medical records examined carefully by the patient’s physician, found notes from the house doctor who attended the patient at midnight on her admission. There was no clinical evidence of impairment, there was no history of drug abuse, there was no evidence of drug impairment. 3. The need to follow-up on urine screening test if it is positive for drugs of abuse in a case where such suspicion is indicated.Link