Hair analysis passive exposure

Goulle, J. R, Noyon, J., and Leroux, R, Nicotine in hair and passive exposure in pediatric pathology, presented at the 2nd international meeting on clinical and forensic aspects of hair analysis, Genova, June 6 to 8, 1994. 

B. Historical Concerns for Passive Exposure in Hair Analysis... 

Yes. In situations where drugs are known to be present in the environment, it is easy to demonstrate that passive exposure can produce positive hair analysis results. In a study by Haley and Hoffmaim of the nicotine and cotinine concentrations in the hair of smokers and nonsmokers, there appeared to be a higher average of nicotine in the unwashed hair of smokers (average 8.75 ng/mg). However, nonsmokers also had an appreciable level of nicotine (average 2.42 ng/mg) which overlapped that of smokers. In contrast, cotinine (the nicotine metabolite) does appear to be a marker of tobacco use in this population. More recently, Kintz and co-workers and Kintz proposed a cutoff level of 2 ng of nicotine/mg of hair to ehminate nonsmoking individuals. Even at this level, some nonsmokers would be positive. 

Not all positive hair analysis results are due to passive exposure. Certainly, many positive results are due to ingestion of drugs. This section clearly illustrates that interpretation of the data must take passive exposure into consideration to determine the source of drugs in any given positive result. 

Mieezkowski, X, Passive contamination of Undercover Narcotics Officers by cocaine an assessment to their exposure using hair analysis. Microgram 28, 193, 1995. 

Particularly troublesome to urinalysis are challenges that a positive result was caused by subversive actions (e.g., spiked food or drink), by passive drug exposure (e.g., poppy seed ingestion), or by sample contamination. We will show in the present paper that hair analysis, by being able to detect such interpretive false positives, is in a much stronger probative position than urinalysis and that this advantage can... 

We have developed special procedures for the avoidance of false positive results and for the accurate interpretation of positive results in terms of drug use, passive exposure to drugs or specimen contamination. This experience with workplace testing will be described along with an assessment of the efficacy and reliability of hair analysis. 

These considerations show clearly that endogenous interpretive false positives are the main problem confronting urinalysis. It is, however, a problem with which hair analysis can provide considerable assistance, since passive exposure as a cause for a positive urinalysis result can be excluded by a positive hair analysis result. As indicated previously, this support is particularly critical in the case of opiates, where considerations of public safety demand that the numerous overturned urinalysis results be further investigated. 

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