Heroin How does LAB DRUG TESTING work?

[iKarley]

Hello everyone
I apologize in advance if this question is something that is now allowed. It isn't really a drug testing question but more of HOW drug tests work

How does LAB drug testing work? Is the urine sample first tested with simple immunoassay as the initial screen and then IF that shows any positives THEN it is tested with the GC-MS methodology? Or are ALL the samples tested with GC-MS regardless?

I used to think that bc it is a lab test that ALL samples were tested by GC-MS but I recently heard that is not true.. I heard the sample is first checked with simple immunoassay method - like a simple dip stick and then if that shows positive then it is tested with GC-MS

Drug testing is something that my friend has been doing a lot of research about lately, thank you so much for the info, I've been really curious..

Thank you in advance for the info!!

 

[sekio]

that's pretty much correct

some labs may gc/ms test all samples or a certain percentage of samples, anyway, just to be sure

 

[iKarley]

Thank you, that pretty much answers my question.

I guess no one would really know for sure unless you spoke with the specific lab testing that specific sample. Thank you for replying

 

[speedballs_over]

GC/MS is expensive, so there's that, at the same time they are 99+% accurate if the operator (a "chromatographer" or "analytical chemist") is qualified, and the lab well run with validated methodologies.

Most labs are good, but an example of a bad lab was one my state formerly ran, used for DUI/Drugged driving cases. Several cases were overturned due to bad results. The chromatography lead chemist in one lab was too liberal, i.e., too easy to report positive results when the chromatography was questionable - near / at the limits of detection for certain compounds she'd always report "positive" rather than re-run the tests, or report N.D. (none detected) if she *thought* there was actually drug / metabolite present. However, the chromatography method(s) were not validated to detect compounds at the extremely low levels that she was calling as "positive", the methods were previously established with the limits of detection above what she was looking at. It's complicated but once you get it, you got it.

We really shouldn't be discussing this but your question seems like you're doing genuine research not trying to avoid a positive test result.

If you have any questions about what the lab processes are hit me up by P.M. I'll answer any questions you might have about the general chemistry, sample prep, instrument accuracy, precision, limits of detection, and specificity of results. As long as you don't ask me how to "fake" samples, I can't reveal that stuff - besides Google will help with that. If you're studying this academically or for the sake of furthering your chemistry knowledge, I'd be happy to assist. I have many years as an analytical chemist writing and validating GC and LC (HPLC) methods for the US generic drug manufacturing industry, B.S. Chemistry 1991.

I now proudly work in the cannabis industry, consulting on analytical issues. Never did I believe theses days would come! I love my cannabis, to get to work on making sure it's of the best quality possible is an amazing opportunity. We use GC/MS and HPLC as primary analytical measures.

I'm sure there's other analytical chemists on this board, we're curious, anal types, you can't spell analytics without "anal" - so true. A lot of us are burners too, legally so in my state!

Apologies for the length, but you hit on my expertise, I had to reply thoroughly. The mod above, was of course correct.

Cheers.

 

[swimmingencouraged]

What are some of the stranger things you run across when testing the marijuanas?

 

[KyFried]

I think it's amazing how we research things like a drug screen and get information from reliable sites like web MD, mayo clinic and other places but we put that information aside and come to a site like this and believe what ever is said by totally unqualified people and with usually so much at stake, simply amazing.

 

[RDP89]

I think it's amazing how we research things like a drug screen and get information from reliable sites like web MD, mayo clinic and other places but we put that information aside and come to a site like this and believe what ever is said by totally unqualified people and with usually so much at stake, simply amazing.

Anyone who does what you described is an idiot. However there are alot of inteligent people here and there are alot of cases where the knowledge isnt even out there, and discussion on a forum such as Bluelight is necessary. That said you shouldnt accept anyones answer as 100% truth without independent verificiation even those from " reliable" sites like the ones you mentioned. Youre pretty much generalizing it all into one big category, which is amazing, simply amazing. Amazingly narrow minded and naive, that is.

 

[Felonious Monk]

What are some of the stranger things you run across when testing the marijuanas?

More of it is moldy than you'd be comfortable thinking about. Especially in states without legitimate access, but even in medical states.