You would need either a separation-and-detection method or a separation-and-identification method.
The first step in both is separation: a family of methods very frequently used by chemists to separate complex mixes is Chromatography (Solid, Gas or Liquid).
If the amount of possible substances is very limited, the separation technique itself serves to identify and quantify the substances. Thin Layer Chroma; Liquid Chroma. Depending on where the spot is on the plate (TLC) or at what time it comes out of the machine (LC), you know what it is; depending on how big the spot (TLC) or the peak (LC) you know how much there is.
When you need to make sure that the substances are identified without resorting to a pre-defined list of “things I may have in the sample”, you need to use LC or GC for separation and send your separated stream into a different analysis that works for identification (Infrared Spec, Mass Spec). A very common combo for this is GC-MS, which means “gas chromatography and then a mass spectrometry”. You get a different mass spec (or IR spec) for each portion that the chroma has separated. In this fashion, if the original sample contained organic substances that you hadn’t thought of, you still identify them.
Of course, testing for “opiates” is easier and cheaper than testing for “specific opiates”, which in turn is easier and cheaper than testing for “lessee what does this guy’s urine have”.
That’s a good point – all of my urine tests were on Federal property, when I was also a Federal employee. Jurisdiction and the amount of process control have a big impact on how easy it is to cheat. As I pointed out, creating such a tamper-proof process is easy, but implementing it may be non-trivial.
Note again that I’m discussing the process of obtaining the sample and maintaining a chain of custody on it, not on the relative ease or difficulty of finding proteases. I’m a mechanical engineer, so the only pro teases I know of are strippers.
What I think zelie zelerton was looking for was a general discussion of drug masking. Not knowing anything about the subject (and yes I realize I’ve just opened myself up for a wealth of criticism) I would imagine that zz wanted something like:
Generally, drugs like X, Y, and Z break down into substances a, b and c in the body. These substances are what is detected in tests. Masking agents can function by a) removing these substances from the body, b) transmuting into substance a’, b’ and c’ which are not detected or c) some other thing I can’t imagine right now.
While some of the answers in the thread explained how to mask a specific drug, they don’t really answer the mechanism question. How does it do that? Why isn’t it detected?
Chasing Dreams answer regarding testosterone did indirectly, in the sense that the test for testosterone (and presumably other hormones but maybe not) tests the ratio between the hormone being used and the mask. Therefore the mask agent is detected along with the doping agent; the quantities aren’t relevant only the ratio.
So I think that is what zelie zelerton was looking for - an understanding of the tests and the functions of the masks, not specific masks for specfic drugs.
exactly, in my world we don’t really care what brand of opiate your on, natural, synthetic, prescription or street, the question doesn’t come up. Hell, half of my pts would “fail” a drug screen after we treat them
I was wondering that too. Do the meds lists and test results get kept private by the testing agency and only certain results get reported to the company?
I used to be a certified Medical Review Officer (whiz quiz doc) and when I trained to do this, the only thing the employer got was a result of “positive” or “negative” or “test not valid”.
A “positive” result was a result that could not be explained by valid prescriptions or other circumstances. In the US, having Heroin in your urine was allways “positive” as there’s no such thing as a legitimate heroin prescription here. Having a masking agent detected would result in a “positive” test too.
But if the patient tested positive for marijuana, but had a legitimate prescription for Marinol (say for nausea from chemotherapy) then he had a “negative” result, which was reported to the employer just as that. “Negative”.
“Test not valid” described where something was weird but the lab couldn’t pin it on any particular.
Things may have changed since then, this was over 5 years ago, IIRC.