Target Analyte Analytical Approaches For Workplace Drug Testing

The target analytes for the workplace drug testing program are amphetamine and methamphetamine. Although there are many other compounds related to amphetamine, particularly the analogs that are of interest, participation in the federal program limits the analytes that can be tested and reported to just those analytes unless the Agency requests and is granted exception. For sports-doping analysis, the limitation is approached differently. In that case there is a list of banned substances that laboratories test for to assess the inappropriate use of 1 or more of these prohibited substances. This list is far greater than for the federal program. When testing samples for purposes such as during under the influence, there are no specific limitations on which drugs are tested, but rather the targeted drugs are those that are commonly associated with impairment while driving. For postmortem analysis, there is also no limitation other than the potential for the analyte to be involved in the cause of death, which in effect comes down to pragmatic limitations of how many different compounds can be assessed in an analytical procedure.

In addition to the limitations imposed by the federal workplace drug test program to the analytes that can be tested, the program also specifies what analytical procedures are acceptable for the analysis of the analytes. Currently, the only approved analytical procedure for the confirmation of the analytes is GC-MS. Testing for other purposes, such as postmortem analysis, require no specific instrumentation. However, the wide acceptance by the forensic toxicology community of the specificity of mass spectrometry, it is the de facto standard used for most analyses in this area as well. The option to expand and use other technologies such as liquid chromatography and multistage mass spectrometry, however, exists within this community, a circumstance that is to their benefit in facing the ever more complex requirements in testing for new drugs, many of which are potent and exist in only very low concentrations in biological samples.

Given the limitations of the federal workplace drug-testing program analytical approaches are limited to GC-MS techniques for analysis of samples. GC-MS itself is a mature and powerful technology, but like all technologies, has its limitations. For purposes of analysis of amphetamine and methamphetamine, particularly at the concentrations related to their cutoffs, GC-MS analysis of these analytes is well-established and validated. To exercise the options described above for other metabolites, and in the case of precursor parent compounds, options to use multistage MS and alternative chromatographic techniques would be advantageous.

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