Evidence for bias in hair testing and procedures to correct bias

A number of in vitro experiments show that different hair samples incorporate differing amounts of drugs under identical conditions. Incorporation of cocaine and morphine tends to be correlated with race, in that the hair of African American females incorporates higher concentrations of cocaine than does the hair of Caucasian males or females. Extrapolation of these data into populations has been fraught with difficulties because the dosages of drugs and their use patterns are unknown. Cosmetic treatments and hygiene alter drug binding, which must be considered in comparing populations because cosmetic treatments are often group dependent. Four reasons are proposed that account for the uptake and retention of drugs by hair and that may differ among groups: (1) permeability and other characteristics of the hair due to genetic influences, (2) cosmetic hair treatments and hair care habits (which may be culturally influenced), (3) drug removal during personal hygiene, and (4) manner and route of drug administration which can affect passive exposure to residual drugs in the environment. The data supporting bias in hair testing are reviewed and methods are proposed that use either the uptake of dyes or the incorporation of drug homologs to reduce bias.     

Evaluation of two immunoassay procedures for drug testing in hair samples

A preliminary initial enzyme-linked immunosorbent assay (LUCIO-Direct ELISA kit) and a preliminary DRI enzyme immunoassay were evaluated for drug detection in head hair with respect to lowered cutoff values recommended in Germany for the control of abstinence in cases of re-granting of drivers' licences. Following drug classes were included: cannabinoids, opiates, cocaine like substances, amphetamine, methamphetamine (and methylenedioxyamphetamines), methadone, and benzodiazepines. 759 analyses were performed using LUCIO-Direct ELISA kits and 936 analyses using DRI enzyme immunoassay tests. Sample size for each drug group and immunoassay test reached from 74 to 178. The LUCIO-Direct ELISA kit revealed a sensitivity of 91% for amphetamine up to 98% for methadone (methamphetamine 92%, cocaine 94%, opiates 94%, benzodiazepines 96%) and values of specificity of 72% for methadone up to 89% for amphetamine and benzodiazepines. The test was not useful for a preliminary screening for tetrahydrocannabinol (sensitivity of 65%) in consideration of a suggested cutoff of 0.02 ng/mg. The DRI enzyme immunoassay test was only useful for morphine and cocaine testing at low recommended new cutoff values (0.1 ng/mg) revealing sensitivities of 94% and 99%, respectively.     

Oral fluid testing for driving under the influence of drugs: history, recent progress and remaining challenges

In recent years the demand for drug testing in oral fluid in cases of driving under the influence has been increasing. The main advantages of saliva/oral fluid are the possibility for non-medical personnel to collect it without embarrassment and a better correlation between presence of drugs in oral fluid and impairment. Several surveys have been performed since the 1980s using saliva, and researchers encountered problems related to insufficient sample volume and insufficient sensitivity of the analytical methods. Steady progress has been shown in sample collection, knowledge of toxicokinetics in oral fluid, reliability of on-site and laboratory-based immunoassays and confirmation methods. In a few countries, legislation was passed that allows the use of saliva as a matrix for screening or confirmation.Despite this progress, some more work needs to be done, principally in the areas of the sensitivity and reliability of on-site screening devices, particularly for cannabis and benzodiazepines, knowledge about passive contamination and more generalised proficiency testing before oral fluid testing for DUID will have the reliability needed to be used forensically.     

Evaluation of the addiction history of a dead woman after exhumation and sectional hair testing.

In Greece, sectional hair analysis, in addition to clinical examination, has been used as a valuable tool for the confirmation of a person's history of drug use. The present report concerns the toxicologic analysis of the exhumed remains and hair samples of an 18-year-old woman. Postmortem toxicologic analysis of blood and urine confirmed recent opiate and cannabis use and indicated that death was associated with heroin abuse. Several months later, the woman's family asked for exhumation and reexamination of the body, insisting that the cause of death was homicide. The investigating judge ordered exhumation and new medicolegal examination of the body. The investigation of the drug profile along the hair shaft was undertaken by analyzing hair sections 1 cm from the hair root for morphine, 6-monoacetylmorphine, heroin, and cannabinoids. The total lengths of the hair samples ranged from 8 to 11 cm. The total morphine levels in the hair sections corresponding to the 3-month period before death were significantly lower (1.5-2.85 ng/mg) than those of the 4- to 10-month period before death (7.4-14.8 ng/mg). An interpretation of these results may be occasional drug use (with considerable attenuation of use during the last 3 months before death). Decrease of tolerance to heroin caused by abstinence and relapse in use could have been the cause of death.     

Futile treatment: the need for legislation and uniform policies

As a matter of social policy, providers should place a top priority on educating colleagues and the public, including lawyers and the courts, so that there is genuine understanding that certain medical conditions, like anencephaly and brain death, cannot be ameliorated, changed, or improved through medical treatment even though the patient may continue to breathe with mechanical assistance for years. If health care professionals do not articulate and adhere to clear, universal standards of practice in this area, the courts will continue to define the duty of the medical profession, and, as Baby K illustrates, that is not acceptable.