There are many things to be said against mandatory drug testing programs. The use of drug tests place the burden of proof on the accused rather than on the accuser. Entire classes of people stand permanently accused on the basis of their membership in the group: all employees (or just all hourly employees), all students, all football players. The tests have the potential of false positives. The required tests are poorly targetted; they look for the presence of chemical substances rather than for the impairment which is the legitimate concern and which justifies the programs.
Each of these concerns is worthy of at least one essay (and possibly all the thousands which have been written). Today, however, I raise a different point.
There is more information in the blood or the urine or the breath than the presence of drugs and drug metabolites.
Let me read your diaries so I know whether you went to a party last Thursday. Show me your credit card statements so I can tell if you went to the store on Tuesday. Give me some of your blood so I can tell whether you took illegal drugs.
Oh, and I promise not to read the rest of the information about your private life.
Yesterday, I willingly shared bodily fluids with my doctor's lab technician. My intent was to provide a great deal of information about my life and my health to my physician. From these samples, they will be able to make excellent guesses about many present and future health conditions that I might be facing. My expectation, of course, is that I will receive useful and well-founded advice of benefit to me.
The sharing of bodily fluids for drug tests is not truly voluntary and is often strongly coerced. The purpose is to protect another person in some way: from the potential of accidental harm, for example, or from the likelihood of lawsuits or public outrage. The expectation is, most often, that no benefit will accrue to the person being tested. (In some cases, a true positive may result in beneficial support being provided to the person. In the case of coercive testing, the individual would be harmed by not cooperating.)
But my point is that there is more information in the blood or the urine or the breath than the presence of drugs and drug metabolites. The person being tested provides a large amount of information which could potentially be used to discriminate against that person. Much of the information (including the presence of drug metabolites in some cases) is sufficiently ambiguous that it can be misinterpretted either from incompetence or from malice.
In most actual cases, this additional information is simply thrown away and wasted. (That in itself suggests the inefficiency of the process but would require at least another essay to explore.) The potential does exist for that information to be exploited.
In the case of financial information provided to the US Internal Revenue Service and the Wisconsin Department of Revenue, many strong barriers are erected in law and practice to prevent the use of private information for other purposes, even quite legitimate ones. The same is true for personal information provided to the US Census Bureau. In the case of drug testing, the personal information not so well protected. It is typically collected by third-party contractors and the results are given to the employer or agency (the second party). Some legal protections exist but the sheer number of entities involved make any practical protections uncertain and unpredicable.
The weight which should be given to these observations can only be ascertained within the context of the whole conversation on the topic of drug tests. Perhaps that is the primary point: We need to consider the full range of issues with all the implications rather than become obsessed with only one or two concerns, however valuable they may be in themselves.