Questions about Labcorp and home testing info

I suppose I should start off with my basic info. I'm fairly tall (6') and weigh approximately 135lbs. I'm not very active (I don't work out but do go hiking or kayaking about once a month) and have been a habitual smoker (4-8 times daily) for at least the past 15 years or so. I typically prefer "b's" as I like a nice buzz but prefer not to be overly high. I do not like to lose control or act messed up. I have been a manager at a marketing company for the past 6 years... I started when the company was small and they never drug tested me as I show up on time and do my job. I recently got an offer from another company and decided to go for it as it was more in line with my optimal career path. I abstained for around 21-28 days (NO cheating) total. Since I am a geek, I do make a decent chunk of change (hence how I was able to afford all these home drug test kits 8 in total, not intended as a brag). I also have a very analytical mind and tend to experiment and research.

My observations on home tests. I bought a 13 panel urine test branded as "First Step". I routinely failed at first. I then started to research this site and others heavily. At first I tried a masking drink called "X-Pulsion x5" which actually worked at the two week marker. I looked at the ingredients and found that it was doing a dilution method. When not masking at this point I still failed for THC. I started stressing out and did several dry runs of the dilution method listed here: http://boards.cannabis.com/drug-test...uidelines.html (mad props to IamN2pot & FakeBoobsRule, FakeBoobsRule... Though I'm grateful for your insight, my ass hates you now due to Metamucil tip). I started testing "clean". I tried Niacin (bull-crap) and makes you feel like crap, GNC products (2-Day liquid Detox kit, also crap)... Only dilution actually had any effect.

I took a home test right before walking into Labcorp today. Strong bars and I followed the dilution guide perfectly. They just collected a sample and will be sending it out. This freaked me out.

My Question: Does Labcorp's pre-employment screening use the GS/MS test? Or is that a fallback when a prior test fails? I've looked all over the net and this site and cannot seem to find any information.

Your (non-idiotic) questions are welcome.

Because of its high cost, the GC/MS is only used to confirm postives that occurred on the initial assay screen.

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Originally Posted by Burnt Toast

Because of its high cost, the GC/MS is only used to confirm postives that occurred on the initial assay screen.

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Thank you VERY much for your reply. It will make the wait much less stressful!

What is it about the GC/MS that invokes stress upon you?

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Originally Posted by Burnt Toast

What is it about the GC/MS that invokes stress upon you?

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It just seems like a much more precise test from what I've read. I was worried that if I do up having to deal with that, the levels would be high enough to disqualify me from a decent paying and less stressful job... I'd basically be working as a contracted geek for the state.

The job has a zero tolerance policy. Bear in mind I can't ask them questions like their threshold (50/ngs?).

This is also the first drug test I've ever taken.

There is no "zero-tolerance" test because every drug testing device has a cutoff threshold and if your urine sample registers below that cutoff threshold, its reported as a negative. Plain, sweet, and simple.

If youre worried about the GC/MS because of its 15 ng cutoff threshold, dont be.
Even though the cutoff thresholds are numerically different, a 50 ng assay screen is functionally equivalent to the 15 ng GC/MS. Their cutoff thresholds are numerically different because the 50 ng assay recognizes the composite of all 31 metabolite concentrations, while the GC/MS recognizes only 1 metabolite concentration. The threshold is set to a numerically lower number because that makes the two types of tests functionally equivalent.

As you may know, THC enters the body in its ingested form and exits the body as 31 different metabolite concentrations. The most prevalent form of those metabolite concentrations being THC-COOH. In order to test negative on the assay screen, the whole composition of the 31 metabolite concentrations must register below 50 ng/ml.

The GC/MS cutoff is at 15 ng because the machine only recognizes one metabolite concentration: the THC-COOH metabolite concentration. In order to test negative, that one metabolite concentration must register below 15 ng/ml.