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Family Physician
Family Physician, Doctor (MD)
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Experience:  Emergency Medicine and Family Practice for over 26 years
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Im having a employer drug test labcorp test 788450 in a few

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Im having a employer drug test labcorp test 788450 in a few days. I had around 8-12 puffs off a pipe 3 weeks ago and prior to that my last use was 6 months ago. Ive passed every at home 50 ng/ml test but from Labcorp's website, they said they use 15 ng/ml. I can possibly push the test back 5 days from now (maybe 7). Will i pass this highly sensitive test for THC? Does the sample automatically get sent for positive confirmation after the initial screen? Im freaking out and this would help. TY
Thank you for your question:

The detection period for marijuana use in urine drug test depends on the frequency of use. With a single use, the detection period is generally in the 3 day range. Even with more frequent use (3-4 times per week), detection is in the 5-7 day range. Daily use will give detection periods in the 10-15 day range.

At this point - 3 weeks past this small single use, there really is no reason to be concerned. You are beyond the detection period even for the ultra-sensitive tests.
Family Physician and 5 other Health Specialists are ready to help you
Customer: replied 3 years ago.
Thanks for your reply, how can you be so sure? Have you had any experience with this type of test? Your answer helps me feel better as I see you're a physician, but my life is depending on this. Is there anything I can do to make sure?
Customer: replied 3 years ago.
Also, your above figures differ significantly from general google searches which state 30-45 days for THC to clear a UA test.

I'm sorry for the delay - I was having weather related internet problems.

Yes, I have had considerable experience with these tests. I am a Medical Review Officer (MRO) - a physician with specialized training and certification in the interpretation of drug tests required by the DOT and other federal agency drug testing programs. I have worked with a number of local employers and universities to establish and supervise their drug testing programs.

The detection period for marijuana is much shorter than most internet references would seem to suggest. Even NORML - a strong opponent of drug testing references this fact on their website:

Detection beyond 30 days is really rare. Here is a link to the actual paper published in Drug Court Review (the article starts on page 23 of the journal)

Here is a reference from a laboratory that offers the "zero tolerance" testing with thresholds of 20 ng/ml for the screening and 5 ng/ml for confirmation. They advertise an expected detection period of "up to 10 days".

Another excellent source is this article from the Mayo Clinic. You will see that the only cases were you may see detection as long as those reported on those websites is with heavy daily use.

I believe the reason many sites repeat the myth of 30+ days for detection is to scare individuals into buying their worthless/fraudulent products that are promoted to "clean", "flush" or "mask" drugs to allow someone to pass a test. If you are convinced that the detection period really is 30 days and you pass a test in less than 30 days after using their product - you are of course convinced (and will tell all your friends) how effective they are. In reality, the reason you passed the test has nothing to do with their product.


In medicine, I try to avoid two words; "always" and "never", but in this case, you are more than 3 weeks from a single low level use, I really don't see any reason to be concerned.