Thank you for allowing me to answer your interesting question. A GC/MS
urinalysis is a dual laboratory test that utilizes a hybrid technology
of both Gas chromatography (GC) and mass spectrometry (MS).
I recommend you first read this article to get a good overview of how
the tests are administered and I think you will see just how difficult
they are to defeat, how accurate they really are and how unlikely they
are to provide false-positive results.
Before I begin let me remind you of our disclaimer at the bottom of
this page. Before forming an opinion about your situation based on
what you learn here, keep in mind that professional advice in this
subject area is always a better course of action than online research.
What I am telling you here is primarily public knowledge that I have
ferreted out for you in an effort to answer your question.
As a general rule a GC/MS test takes about 23 minutes to run. However,
most testing labs have quite a number of samples (simply by virtue of
what they do) which they run all at the same time in an autosampler.
Fifty samples, for example take about 24 hours to run. Even then,
after the run is complete, a technician must examine each of the
spectrum results from the chromatograph and log where the peaks have
indicated the presence of specific substances with regard to each
individual sample. The process is time consuming and I find it
questionable that any lab contracted by en employer to perform a
random drug screen not involving an emergency issue would have only
one sample to test and would return the results via fax in just 24
hours. Such a report is theoretically possible, I suppose, but in my
opinion not at all typical of what the process normally entails or
what testing time normally permits. Here you will see an article from
the Mississippi State Crime Lab (one of the smallest and least busy of
all state crime labs in the United States) where this very issue is
discussed. Clearly a state crime lab receives the most serious and
urgent testing requests of any submitted and even THEY say that 50
samples take a minimum of 24 hours to spin up.
State Crime Lab Uses Combined Scan/SIM by GC/MS to Boost Drug Analysis Throughput
In any laboratory test there is a potential margin for error relative
to equipment, chemical, environmental, intentional tampering,
unintentional contamination or human error. There is NO urinalysis
that is 100% ?foolproof?. In fact, in my estimation a GC/MS test is
probably as close to error free as a drug screen urinalysis test can
be yet even this test can, and sometimes does, have problems because
of the factors I mentioned. This level of accuracy is typically why
the GC/MS if most often used as a second confirmation test rather than
an initial (and less expensive) test. The federal government considers
the GC/MS test the ?gold standard? of urinalysis tests and is one of
the few agencies that I know of that administer this type of test as
an initial analysis (though others may do it that I am not aware of).
How do I know this? Well, as it turns out I actually happen to be a
law enforcement evidence technician with more than 20 years of law
enforcement experience; six of which are in this particular field or
work. While I do not perform the actual GC/MS tests myself I do
prepare forensic samples for testing, have some working knowledge of
such tests and act as a liaison between a law enforcement agency and a
notable state crime laboratory.
While Advil (Ibuprofen) can sometimes result in a false-positive for
THC in some tests, a GC/MS should have detected it, identified it and
isolated that detection from the naturally occurring and illicit
substances (if any). In my own work the test results I typically
receive list all the known elements that the GC/MS has identified.
As a rule, a GC/MS test detects what is PRESENT and not only for the
presence of something IN PARTICULAR. In other words, if you were
taking Advil, ?Ibuprofen? should have also been listed on the results
as one of the detected substances. If THC was present
?Tetrahydrocannabinol? should have also have been listed on the
results. On some lesser reliable tests where a specific substance is
tested for and a false-positive has occurred, THC might show up IN
LIEU OF Ibuprofen but rarely do these both show up because that is not
the nature of the test. You see what I mean? They test for THC, detect
some other substances that creates a false-positive result indicative
of the presence of THC, but the test results shows ONLY THC and not
the interfering compound because that compound was not specifically
tested for. A GC/MS doesn?t normally provide this kind of result
because it doesn?t JUST say there is A SUBSTANCE in your urine sample;
it indicates WHAT ALL WAS DETECTED in the urine sample. That?s why
this type of test is considered a gold standard.
You will see here in this chart prepared by Toxicology Associates,
Inc., a company that tests blood, serum, urine, and solids for trace
evidence of various substances, lists Ibuprofen (Motrin, Advil)
specifically as one of the substances that a GC/MS test is designed to
identify and detect.
TOXICOLOGY ASSOCIATES, INC
Having said that, the best we can do is to say, ?Yes, it is POSSIBLE
that your sample was subjected to a GC/MS test and it is POSSIBLE that
through some interference the test provided a false-positive result?.
Not knowing your employer, her ethics or perhaps her underlying
motivation (as you suggested) it is also POSSIBLE that you are being
misled. The fact that you were promised a follow-up test that never
occurred, given the fact that you already suspect you are being
unfairly targeted, does give rise to suspicion in my opinion. If we
are to assume the GC/MS test was a typical test with typical results,
the fact that your sample was supposedly subjected to a GC/MS test and
ALL detected substances were not on the results (if they was the case)
is also an issue to consider. Since the legal implications vary from
state to state and we are prohibited from offering legal advice, it is
probably in your best interest to consult an attorney if the issue
rekindles and takes a turn for the worst. Otherwise, in the event
nothing more comes from it, maybe you should just cut your losses and
let the subject go.
I hope you find that my answer exceeds your expectations. If you have
any questions about my research please post a clarification request
prior to rating the answer. Otherwise I welcome your rating and your
final comments and I look forward to working with you again in the
near future. Thank you for bringing your question to us.
Tutuzdad-ga ? Google Answers Researcher
Tests on Trial - - Jobs and Reputations Ride on Unproven Drug Screens
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