How many Nanograms for Pre-employment?

Discussion in 'Urine Testing' started by keef0420, Apr 2, 2009.

  1. keef0420

    keef0420 New Member

    Trial run I diluted as per N2 instructions and used certo. I took a home test 2 days prior to the real test that was at 50 nanograms. I BARELY passed with a VERY faint white line

    Test day I diluted as per N2 instructions and used certo. I smoked 10 days prior and am a regular smoker. I subbed clean urine as main but they wanted me to fill to a higher line than the 2 oz I had, so used about a 1/5th of my own dilurted urine.

    I just read somewhere that the military test for 15 nanograms. What is the cut off for pre-employement? The company I am working for is regulated by the FDA and the physical I got was REALLY hardcore.

    I am worried that if I was at 50 nanograms from the home test with the diluted if I mixed my sub it might mix together somewhere around 15-20. I might fail a test that goes that low.

    Thanks in advance! Getting real paranoid :confused:
  2. Secs

    Secs New Member

    Most pre-employment drug tests are at 50 ng/mL. BTW, the military tests are also at 50 ng/mL for THC on the initial immunoassay, and like most other tests, use 15 ng/mL for the confirmation GC/MS test.
  3. keef0420

    keef0420 New Member

    So the confirmation GC/MS test that uses 15 ng/mL is only ran if you fail the intial test?
  4. keef0420

    keef0420 New Member

    I alsao know that the lab/clinic I had it done at was "sending some out" so I am worried they may have been doing gc testing anyway since the physical was so hard and intense
  5. Secs

    Secs New Member

    The laboratory where "they send some out" to, will do an immunoassay. THEN, and only THEN, if the specimen screens non-negative on the immunoassay, is the specimen confirmed with a GC/MS method.

    Don't look for problems where there are none.
  6. keef0420

    keef0420 New Member

    The only reason I am bugging out is because the test was done at concerta. I saw another post here:

    http://www.marijuana.com/urine-testing/108586-yet-another-i-failed-but-question.html

    where the person failed and had the test done at concerta where it was sent out and the failed results were at 47. Maybe the immunoassays resulted at around 50 and that is why they did the gc / ms for that person

    THe physical was HARD CORE and the techs at concerta where even suprised at HOW much I had to get done. The job is for a company regulated by the FDA and I am just worried that they may requested the gc / ms right off the bat.

    I called for the results from the physical and the woman handling my case at national medical(the place that sent me to concerta) and she said they had everything back except for the chest xray. I hinted around and said I am waiting on the results to give notice to my current emplyer and wanted to make suire I didnt have to get anytthing retested with glucose levels on the blood work or the drug screen. She said oh no, but wouldnt clear me until the xray results came in.

    FINEGERS CROSSED:dizzy:
  7. Secs

    Secs New Member

    The cutoff for the GC/MS test is 15, that is why it was reported as a positive. The immunoassay detects about 31 different specific marijuana metabolites at a yea or nay at 50 ng/mL. The GC/MS only focuses on the most common marijuana metabolite at 15 ng/mL.

    There is no way any specimen will be sent to a GC/MS without an immunoassay first. For one thing, they wouldn't know which drug to run the confirmation on, and for another, it is just too expensive to run the confirmatory GC/MS on all drugs in a given panel.

    Don't let your paranoia get the better of you.
  8. keef0420

    keef0420 New Member

    Thanks for the infom and holding my hand sec!

    I will be sure to post the news of passing results when I get them. Thanks!
  9. keef0420

    keef0420 New Member

    The only other thing that I still dont understand tho is:

    if that guy from the other thread failed the gas spectroscopy and the fail was 47 nanograms, what gave concerta the red light to gas spectroscopy his sample in the first place? if he failed at 47 wouldnt he had to have tested at above 47 on the immunoassay to send it to spectroscopy?

    Just trying to understand why you would ever get sent to the gas spectroscopy level and not have a result ABOVE 50 nanograms if 50 nanograms is the cutoff to to send you to gas spectroscopy.

    Is it possible that he tested around 50 or so nanograms on the immunoassay and then when the did a gas spectroscopy test on his highest metabolite it was a more precise test than the immunoassay and that gave the 47 naanogram results?

    Sorry if I am being paranoid. Just trying to BEST understand the way the procedure works.
  10. lew scannon

    lew scannon Banned

    It must be first understood that THC enters the body in its ingestible form and exits the body as 31 different metabolite concentrations, the most prevalent form of the 31 concentrations is THC-COOH.

    Like Sec stated, the assay recognizes the composite of all 31 metabolite concentrations. In order to test negative on the assay, the composite of all 31 concentrations must test below 50 ng

    The GC/MS has a lower cutoff because the machine only recognizes one metabolite concentration - the THC-COOH. In order to test negative, the THC-COOH metabolite must test below 15 ng.

    So even though the cutoff levels are different, the two types of tests are essentially equivalent. Therefore a GC/MS reading of 47 ng THC-COOH, is equivalent to being more (much more) than 50 ng of all 31 metabolites as recognized by the assay. Exactly how much more is not known, as assays do not have the ability to yield a specific quantity number (unlike the GC/MS) .
    4 people like this.
  11. keef0420

    keef0420 New Member

    ok that makes sense lew scannon. I just wanted to fully understand it.

    just being a devils advocate, but couldn't a company theoretically request that gc/ms THC-COOH be ran regardless and maybe pay for the higher fee and a few other common drugs like cocaine etc? They already shelled out a ton and bells and whistles on the physical like chest xray, pulmonary function test(which I almost couldn't pass...from pot I would assume), and blood etc.
  12. Secs

    Secs New Member

    Being that you are working perhaps around medications or other substances, they want to be sure you aren't under the influence of many, many other drugs. There is such a thing as a medical panel (several, actually) that can test for as many as 50 - 75 different specific drugs and derivitives of drug bases. To be able to test for all, they need to do an immunoassay on all of them, because it would run in the thousands of dollars to do a GC/MS on all of them.

    Drug tests just aren't conducted in that manner.
    2 people like this.
  13. keef0420

    keef0420 New Member

    I passed!

    Sorry for the slow reply. Ive been busy with the new job. Thanks for all of your help
  14. booboo

    booboo New Member

    Well guys going in now. I may or may not still have a job in a week....ill keep you posted

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