Hair analysis results have been admitted as evidence of drug use and exposure by federal and state courts.
Hair drug tests and other forms of drug screening are highly controversial. With new U.S. government guidelines that seek to expand drug testing, analysis of the accuracy of hair drug tests are being analyzed by a wide range of legal and medical professionals. Workplace drug testing is being criticized on general terms as there is controversary over whether a positive drug test result has any meaningful relationship to work performance and it encourages lifestyle discrimination, is an invasion of privacy and smacks of an Orwellian “Big Brother” attitude In government and the workplace. In spite of misgivings about the efficacy and accuracy of hair drug tests and other drug screens, millions of people now or will be subject to random drug testing at work and home. Putting aside the implications of the new federal drug tests that have been proposed, hair drug tests are becoming more common in business settings, public and private schools, and at home.
Workplace and home drug test kits are easily obtained despite the fact that they are not easily and accurately administered. Hair drug tests are becoming more commonplace because most drugs rapidly disappear in saliva, urine and blood.
Although nearly everyone freely acknowledges that the testing of hair for drug residue and levels of various drugs is a difficult proposition and may not be as reliable as other forms of drug screens, hair drug tests are on the rise. The prevalence of false positive results from second hand marijuana smoke is very high. These inaccurate results, which take the form of false positives in which a positive drug test result occurs where there is no drug use and a negative drug test result where there has been drug use occurs quite often, especially in home and work where drug testing kits are used under non-laboratory conditions.
Legal challenges are becoming much more common. The basis for these legal challenges are subject to a variety of factors including local rules of evidence, relevance to the case, whether there is probable cause, presence of valid court orders and warrants, whether there were voluntary or coerced statements, the scientific methods, and historical accuracy of the laboratory administering hair drug tests.
Several legal considerations come into play including the rules regarding expert testimony and varying standards of proof in civil, administrative and criminal proceedings.
Expert testimony concerning hair drug tests and their admissibility in the United States, is governed by a number of rules and case law, most notably Frye v. U.S. 1923, and Daubert v. Merrell Pharmaceuticals, Inc., 509 U.S. 579, 1993).
The admissibility of expert testimony is also heavily influenced by the Federal Rules of Evidence. In Daubert v Merrell Pharmaceuticals, the United States Supreme Court ruled on new standards for determining what scientific evidence would be admitted in Federal courts. This ruling, commonly referred to as the “Daubert Rule” states that “the reasoning or methodology underlying testimony must be scientifically valid. Examination of the scientific validity include: widespread acceptance; peer review; publication; testing; rates of error; the existence of standards.
Varying standards of evidence in different venues and proceedings often come into play with cases involving hair drug tests. It is important to understand that drug test results are used as evidence in civil and criminal cases. Such evidence is often more influential in civil proceeding as the evidentiary preponderance in civil cases rests on the concept of “more likely than not likely” while criminal cases uses the concept of “beyond a reasonable doubt”.
U.S. courts have had different responses to evidence given as the result of hair drug testing. Most experts expect that hair analysis that seeks to detect drug use will continue to be presented in civil and criminal proceedings despite issues surrounding the accuracy of hair drug tests.