GC MS Drug Test

3 Aug


Welcome to the GC MS Drug Test guide.

Most every thing out there on the internet about GC/MS drug testing is based on a small section of a 1998 FAQ written by Justin Gombos, currently archived at Erowid. You will quickly see again and again the same information copied verbatim from this guide on various websites about passing drugs tests. Since then, GC/MS hardware has gotten both cheaper and better. It is my hope to write a more up to date guide than what’s currently out there and offer the abilility to keep is up to date via reader participation and comments.

Please add your comments if you see something that is inaccurate, incomplete, or misleading. This is a work in progress. Thanks – Ben | dreaminglife.org

Understanding GC-MC Drug Testing Procedures

Getting into the details of how GC MC works gets real scientific, real quick. For our purposes here, let’s can simplify the process by explaining it this way:

How Gas chromatography / mass spectrometry Works
1. The GC technique is used to separate compounds from the supplied sample
2. The MS technique is then used to identify those compounds based on their molecular structure
3. Working together, GC MS tests can isolate compounds and identify them based on their molecular structure.

Because of this ability to idenfity specific compounds and substances, GC-MS testing is ideal for things like:

  • drug testing
  • environmental contamination analysis
  • pesticide contamination identification
  • fire investigations
  • explosives investigations
  • general sample testing and confirmation
  • airport security substance testing
  • trace element identification
  • criminal investigations
  • forensics toxicology

While these other applications are interesting, this guide will focus on the first application: the GC MS Drug Test.

What Drugs Can Be Detected With an GC MS Drug Test?

Gas chromatography-mass spectrometry tests identify substances against a database or set of databases. Any substance that is in those databases can be detected. Theoretically this means any and all drugs can be detected using such tests. Practically, it likely means that every major class of drugs is included in a GC MS drug test. Note, however, since many times these tests are used to confirm the result of a prior test result (under a different method), companies paying for GC MS tests will be looking to confirm that specific substance only. Ths likely means opiates, PCP, methamphetamine, cocaine or marijuana.



Detection Rates for Gas chromatography–mass spectrometry Drug Testing

Detection rates depend on the substance being analyzed.

  • For hair tests, detection rates go back roughly 3 months or 90 days. Substances consumed during this period will have a detectable drug metabolite in the sample.
  • For urine tests, detection rates vary depending on the substance in question:
    • marijuana (single use) – 2 to 3 days
    • marijuana (consistent/daily use) – 14 to 30 days
    • cocaine – 4 to 5 days

For detailed detection information by substance, click here for a chart from Erowid.

How Can I Pass a GC MS Drug Test?

As far as I can tell from all my research, the only way to pass a GC/MS drug test is through submitting a clean sample free of all drugs.

This leaves two options:

You will pass by submitting your own clean urine or someone elses.

In other words, this test cannot be cheated with detox products, creatine, niacin (warning – see niacin flush drug test, etc. I suspect that individuals submitting fake urine would have their results voided, as a test at this level of scrutiny seemingly should be able to detect fake urine. (confirmation needed)

Some notes:

  • Products like UrineLuck contain potassium nitrates which will attack drug metabolites (THC only? confirmation needed) in the body, thus effectively detoxing the sample as far as drug tests is concerned. However, GC/MC testing labs know this and thus look for nitrate levels in the sample. If abnormal levels are found, the test is considered adulterated or voided.
  • This type of testing is the most expensive. As such, it typically is not used for employment testing or at home drug testing.
  • Instead, GC/MS drug tests are used to confirm the results or a prior test.  For example, if the hair sample mailed in as part of the HairConfirm hair follicle test returns a positive result for a substance, the company double checks this result using GC/CS.



Who Uses the GC MS Drug Test

What Labs Use or Offer GC MS Drug Tests?

Note: Nearly all these laboratories use GC-MS testing only to confirm previous test results done by urine or hair.

  • Confirm BioSciences (HairConfirm) (source)
  • Omega Laboratories  (source)
  • AmeriDrug Labs (source)
  • Fas Tes Drug Testing (source)
  • Craig Medical Distribution Inc (source)

Sources and Recommended Reading


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