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I recently took a pre employment drug test. I received results that I failed with 44ng ml. If my cutoff was 50ng ml for the initial test, why was it sent for confermation testing? Shouldn't my test been reported as negative with a result of 44ng ml with a cutoff 50ng ml?
Initial test cutoff-50ng ml
Confermation test cutoff-15ng ml
My results:
Initial test-44ng ml
Confermation test-44ng ml
Something is very fishy here. An Immunoassay is used when conducting the initial screening. All Immunoassays are a Pass/Fail endeavor and have no ability to yield quantitative values. So with that being pointed out, how can they come up with 44 ng (or any quantitative value for that matter) on the initial?Quote:
My results:
Initial test-44ng ml
Confermation test-44ng ml
In order to obtain quantitative values, the sample must be run through the GC/MS (which is used for the confirmation test).
So all GC/MS testing should prove to be over 50ng ml given the the sample even qualified for conformation testing?
The GC/MS carries a cutoff threshold of 15 ng and is used for the confirmation test only. It would be way too costly for both the lab and client for the GC/MS to be used as the primary methodology. Thats why theres an initial Immunoassay screen.Quote:
Originally Posted by Foggy22
I understand that. Is the Lab charging for uneccissary test? If the confirmation test is under 50 that means there wasn't a need for it in the first place right?
Quote:
I understand that. Is the Lab charging for uneccissary test? If the confirmation test is under 50 that means there wasn't a need for it in the first place right?
Not sure what youre trying to ask here.
The confirmation test (GC/MS) is used only if the urine sample registers a "non-negative" for any of the drug panels on the initial I/A screen. So if a urine sample tests negative for all of the drug panels on the I/A, the test is over as a "pass" - no confirmation test is performed. It would make no economical sense to both the lab and client to run a confirmation GC/MS test if a urine sample tests negative for all of the drug panels on the I/A. It would run into the hundreds, if not thousands, of dollars to run the GC/MS on all of the drugs on a given panel.
Drug tests are just not conducted in that manner. Like all businesses, labs are into making a profit and they are not going to run unnecessary tests that could eat away at their profit margin.
And no employer in their right mind of business is going to spend that kind of money on such unnecessary tests, especially if they have a sizable number of workers on the payroll.
Ok....so with a cutoff of 50ng ml, my 44ng ml should of passed correct?
Yes it would. But again, like Ive pointed out previously, Immunoassays lack the ability to quantify - they are a pass/fail endeavor only.Quote:
Originally Posted by Foggy22
I understand that completely. I'm confused as to were the 50ng ml comes into play
The I/A carries a 50 ng limit because, being a non-selective methodology, it recognizes all 31 metabolite concentrations combined.Quote:
I'm confused as to were the 50ng ml comes into play
THC enters the body in its ingested form and exits the body as 31 different metabolite concentrations. The most prevalent form of these 31 metabolite concentrations is the THC-COOH metabolite concentration.
In order to test negative on the I/A, the whole combination of the 31 metabolite concentrations must register below 50 ng.
The GC/MS carries a lower (numerically) cutoff threshold at 15 ng because, being a selective and more accurate methodology, it recognizes only one metabolite concentration - the metabolite concentration that matters the most, which is the THC-COOH metabolite concentration.
In order for the urine sample to test negative on the GC/MS, only that one metabolite concentration (THC-COOH) must register below 15 ng.
Even though their cutoffs numerically differ, a 50 ng Immunoassay is functionally equivalent to the 15 ng GC/MS. The cutoff has to be set at a lower number in order to make the two types of tests functionally equivalent.
Do I have any grounds to throw a bitch fit and dispute these results?
I would, because somebody is blowing smoke up your rump in regards to the "44 ng for the initial" when the initial assay screen has no ability to give a quantitative value.Quote:
Originally Posted by Foggy22
Will do, many thanks!
Protested, won, taking me retest in about 10 minutes!!