Cut off levels

Discussion in 'Urine Testing' started by abc12, Oct 1, 2005.

  1. abc12

    abc12 New Member

    Hi , Wanted to know if the immunoassay cut off level of 50 ng is the same as the GC/MS cutoff level of 15ng? If you are at 50ng or less on a home test (negative) does this mean you are at 15ng or less(also negative) on the GC/MS also ? Just confused on the different numbers of 50ng and 15 ng. Can you please explain?? Thanks for any info.
  2. grillmeats

    grillmeats No Longer Active

    You will pass if you passed a home test, they use the same cutoff. Be sure you dilute right for the real test. They may check for S Gravity, that's were salt and the creatine come in.
  3. abc12

    abc12 New Member

    If I passed 2 hometest( a few weeks apart) without using the dilute method . Should I still dilute for my test? Been clean 58 days. Thanks for all the help.
  4. grillmeats

    grillmeats No Longer Active

    You Passed

    58 Days, You Passed , Not 1, but 2 Home Tests. A Few apart! No doubt, you will pass.
    Stay on your toes and do what you are doing. If you are thinking of toking, DON'T. Get it over with and then think about your future.
    GrillMeats
  5. abc12

    abc12 New Member

    I truly want to say Thanks. You have been Great.
  6. trade04

    trade04 New Member


    are you sure its the same cut off? why would one say 50 and the other 15? does this just mean the amount of urine being tested? or does it check for certain metabolites that take slightly longer to excrete?
  7. grillmeats

    grillmeats No Longer Active

    It A Gravity Factor

    When diluting, your urine, even if clear, still has salt and levels of creatine in it. As far as the THC goes a home test will give a close enough result to any test. Of course there is always that chance, but with 58 days clean, it's a rare.
  8. lew scannon

    lew scannon Banned

    GM is right in saying that the home test utilizes the same cutoff level as the EMIT/EIA screen.
    The screen cuts off at 50 ng/ml because, being a simple assay, it recognizes a composite of 31 metabolite concentrations. As you probably know, the psychoactive ingredient in marijuana is 11-nor-D-9-tetrahyrocanibinol (THC). This is oxidized by the body and comes out as 31 different metabolites, the most prevalent form being the 11-nor-D-9-tetrahyrocanibinolic acid (THCA) metabolite. If the sample is below 50 ng, the test is over as a passing status.
    If the sample is above 50 ng, the sample gets sent on to a GC/MS for confirmation. The GC/MS cutoff is lower at 15 ng because the machine only identifies one of the 31 metabolites, which is the 11-nor-D-9-tetrahyrocanibinolic acid. To pass the GC/MS, that one metabolite must be below the 15 ng/ml cutoff.

    Hope that helps a little
    :cool:
  9. trade04

    trade04 New Member


    ok thanks someone finally got it cleaned up for me. Basically i wanted to know how the machine worked cuz i might be tested on one, and if they try to im gonna refuse and ask for an EMIT, because i wasnt aware of how soon i would be tested on the machine (ill use an alcohol excuse, because it test for that also)
  10. lew scannon

    lew scannon Banned

    Trade, the GC/MS is not used as the primary analysis. It would be too costly to run a GC/MS on every urine sample. Instead, the GC/MS is used for confirmation of a screen positive. The initial analysis will consist of an assay screen of some type; whether its an EMIT, FIPA, EIA, etc.
  11. grillmeats

    grillmeats No Longer Active

    Thank Goodness

    lew scannon I owe you for this, and I will fiqure a way to pay you back. We always need support and you have supported me with these chemical dialogs. I am impressed and I know N2 and you were familiar with each other.
    Please PM me and we'll talk.
    Marty I Mean GM
  12. trade04

    trade04 New Member

    omg forget it im tired of explaining that they have a gc/ms computerized system from DELL. its faster and more efficient, and almost impossible to pass unless you abstain, forget it im just gonna stop thinking about it because theres nothing i can do anyway, i smoked to bad 4 me!!! let god handle it
  13. grillmeats

    grillmeats No Longer Active

    Sorry

    I want to make things clear, and if you have an additude, I suggest you put in a SAFE!
    Lew and I have communication with each other.
    GM
  14. lew scannon

    lew scannon Banned

    Mmmmkay. For the sake of argument, even on the off-chance of conducting the GC/MS as the primary analysis, you could always substitute, using the Quick Fix or a clean sample from someone. Substitution works on any type of drug test, whether its a screen or a GC/MS.
    And you don't have to abstain from the Great God Gangja :D


    Thanks for the kind words Mar, er-uh, GM. :laugh:

    Oh yea, N2 & I go back a pretty good way. I havent heard from him in a while though. At least not since the beginning of summer. He took a similar hiatus last year to do some flying, but his abscence never lasted this long (N2oooo, WHERE ARE YOOooo?)

    And if theres anything you like to discuss outside this forum, feel free to PM me anytime.
    :chokin:

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