Originally published in (eds. Edward. J. Cone, Ph.D., Michael. J. Welch, Ph.D., and M. Beth Grigson Babecki, M.A.) Hair Testing for Drugs of Abuse: International Research on Standards and Technology, 1995, p. 91-120. NIH Publication No. 95-3727.

ANALYSIS OF HAIR FOR COCAINE

Gary L. Henderson, Martha R. Harkey, and Reese T. Jones



The use of hair as a specimen to detect cocaine use was first reported in 1981 (Arnold and Püschel 1981; Valente et al. 1981). In those studies, hair samples from suspected drug abusers were analyzed by radioimmunoassay (RIA) for the cocaine metabolite benzoylecgonine (BZE) in an attempt to verify a history of cocaine use. Additional studies using RIA followed shortly thereafter (Arnold and Püschel 1981; Valente et al. 1981; Baumgartner et 1982; Smith and Liu 1986; Michalodimitrakis 1987). The first gas chromatography/mass spectrometry (GC/MS) procedures for detecting cocaine in hair were not reported until 1987 (Balabanova and Homoki 1987). When this more specific technique was used, it was found that cocaine, not BZE, is the primary analyte in hair. The metabolites BZE and ecgonine methyl ester (EME), shown in figure 1, are present in such low and variable concentrations that they may result from environmental degradation of cocaine already present in hair. Because of the lack of specificity used in some of the early studies, it is difficult to evaluate much of this literature. For example, some investigators quantitated "cocaine" in hair using RIA antibodies highly specific for BZE, whereas others used RlAs more specific for cocaine. In addition, some digestion or extraction procedures could have caused degradation of cocaine.



FIGURE 1. Chemical structure and molecular weight (MW) of cocaine and the metabolites
benzoylecgonine, ecgonine methyl ester, cocaethylene, and norcocaine.

The past few years have seen the development of highly specific and sensitive GC/MS methods for the simultaneous detection and quantitation of cocaine and several of its metabolites in hair. These methods have been applied to hair samples obtained from a variety of animal species and human subjects. It is now clear from these more detailed studies that in all species studied and by all routes of administration, cocaine is incorporated into hair as the parent drug and can be detected in hair for months after administration. What has not been determined is the relationship between the dose and the amount of drug in hair or whether the position of the drug along the hair shaft can be used to determine the time of drug ingestion.
[edited here for brevity]

Dose-Response Relationships

The correlation between the dose of cocaine and the amounts of drug and metabolites detected in hair is unclear at the present time and remains controversial. Most studies have shown few correlations between dose of drug and concentration found in hair.


On the other hand, Martinez and colleagues (1993) analyzed hair samples from Hispanic males attending a community outreach program and concluded that hair analysis could identify drug use that was not detected by urinalysis; however, there was no particular relationship between the stated frequency of cocaine use and the levels of cocaine and BZE in the hair of their subjects. Möller and colleagues (1992) found no correlation between concentrations of cocaine or metabolites in hair and the reported use patterns of South American coca chewers.

Controlled-Dose Studies. The authors administered precise doses of cocaine-d5 to 25 subjects under controlled clinical conditions and used GC/MS to quantitate the cocaine, BZE, and EME incorporated into hair (Henderson et al. 1993). A poor correlation was found between the dose administered and the amount of drug (cocaine-d5) incorporated into hair. Under certain circumstances, increased doses did result in an increased amount of drug incorporated into hair; however, because of the considerable intersubject variability, it was impossible to infer the dose administered from the amount of drug in hair. However, the doses administered in the study were limited because of ethical and safety considerations and were no doubt considerably less than what might be used by compulsive cocaine users.Hair as a "Calendar" of Drug Intake

The authors found that it was difficult to estimate precisely the time of drug administration from the position of cocaine along the hair shaft. In some subjects' hair, sectional analysis showed that cocaine was confined to a relatively small segment of the hair shaft and that it migrated with time along the axis at a rate of about 1 cm/month, the reported hair growth rate for humans (Saitoh et al. 1969, pp. 183-201; Montagna and Parakkal 1974, pp. 83-105). However, in many subjects little correlation was found between the position of the drug along the shaft and the time since drug administration. Variables that contribute to inaccuracies in correlating position of drug along the hair shaft with the time of drug ingestion include intersubject differences in hair growth rate, measuring hairs in different phases of their growth cycle, and variability in alignment of the hair strands prior to cutting. Hair growth rate can vary threefold among individuals (0.5 to 1.5 cm/month) (Saitoh et al. 1969; Montagna and Parakkal 1974, pp. 83-105).

Uematsu and colleagues (1993) used a single dose of a quinolone antimicrobial to measure hair growth rate in human volunteers and found the drug was distributed widely along the hair shafts (5 to 7 cm) when five strands of hair were measured. However, when only one strand of hair was measured, the drug was restricted to a 1- to 2-cm portion of the shaft. This suggests that there may have been some variability in aligning the hair prior to cutting or that not all hairs in the sample were in the growing phase when the drug was ingested. Finally, because cocaine is excreted in sweat, it is possible that the drug may be incorporated directly into hair as the hair emerges from the scalp.

External Contamination as a Potential Source of False Positives

The possibility that a positive hair test for cocaine could result from external contamination is an important consideration when interpreting the results of a hair test. A few investigators have shown that washing can remove all externally deposited cocaine (Baumgartner and Hill 1992, pp. 577-597; Koren et al. 1992b). Others have found that hair exposed to cocaine in aqueous or other solution will accumulate large amounts of the drug; that washing will remove most, but not all, of the accumulated drug; and that the amount remaining will be consistent with very heavy drug use (Cone et al. 1991; Henderson et al. 1991; Welch et al. 1993; Blank and Kidwell 1993). The National Institute of Standards and Technology prepares reference materials by soaking hair in a solution of dimethylsulfoxide containing cocaine, BZE, morphine, and codeine. These materials are provided to laboratories as proficiency samples to evaluate the accuracy and precision of the laboratories' methods. Until this issue is resolved, external contamination should always be considered when interpreting hair analysis data, and both the collection site and the testing laboratory should have rigorous quality control measures to prevent contamination of any specimen. It has been proposed that unique metabolites such as cocaethylene or norcocaine be used as indicators of active exposure; that is, these metabolites, as well as cocaine and BZE, should be present in any hair sample declared positive (Cone et al. 1991). However, these metabolites are present in low, often undetectable, concentrations. In addition, cocaethylene or norcocaine has been identified in contraband cocaine samples, although this is likely a rare occurrence (Janzen 1992).




http://www.druglibrary.or...kehair.htm


After researching this, I've changed my mind. The cop is probably telling the truth. And his actions (breaking up w/ girl, not even coffee, different environments-same behavior, no indicators of drug use [ I say this because I'm sure they looked, including financial records like ATM visits . . .]
I wonder if he had union representation at the drug test?
If he were fired for failing to submit to the hair test, but would submit to blood or urinalysis it would be interesting to see if he'd get his job back.
But urinalysis and blood are both more invasive than a hair sample.

SUPRMAN said:

I posted 'em. Did you miss it???

luv4u said:

This is a very popular emoticon in this thread.

Damn man, you got a lot of time on your hands. Hell I ain't got time to read all of that.