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Family Physician
Family Physician, Doctor (MD)
Category: Health
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Experience:  Emergency Medicine and Family Practice for over 26 years
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Will I pass urine drug test if I smoked weed 18 days ago?

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If I smoked weed 3 days in a row, 18 days ago, will I pass a urine drug screen test tomorrow? I hadn't smoked in 6 months except for those three days 18 days ago.

As a Medical Review Officer (MRO), trained and certified in drug testing interpretation - I would say:

For truly occasional use such as you describe, the detection period is shorter. Depending on the sensitivity of the test (some employers use "zero tolerance" testing thresholds, the detection period is typically in the 3-5 days (7-10 on the high sensitivity testing)

Customer: replied 7 years ago.

So just to be clear, with the conditions I described, there will be no detection since it has been 18 days since I smoked for three days in a row and 6 months prior to the those three days? The link you sent doesn't say how much or for how long the tests are valid.

The link that I provided is from a laboratory that offers the "zero tolerance testing". It reports the period of detection - the time for which the test would be expected to be positive.
Here is another reference from Mayo Clinic
Table 2 of this document includes the following detection periods;
Single use........3 days
Moderate use (4 times/wk)......5-7 days
Daily use.........10-15 days
Long-term heavy smoker..........greater than 30 days
Unfortunately, many sources on the web (particularly those promoting fraudulent products that claim to "clean" urine) report the 30+ day range. Then when some unsuspecting person purchases their completely useless product and passes the test they believe that the product actually did something useful.
Obviously, the accuracy of the information that you provided (number of days used, time since use and frequency) are key. If you are not being truthful with that information - then a longer detection period would possibly apply.

Customer: replied 7 years ago.

That is the exact usage. Nothing for 6 months, then smoked for 3 days, then nothing for 18 days after that. So judging by your info, I should pass. Right?

YES, based on the medical literature you would be expected to test negative on a urine test. (I should mention that hair testing can be positive for 3-4 months).

Family Physician, Doctor (MD)
Category: Health
Satisfied Customers: 12816
Experience: Emergency Medicine and Family Practice for over 26 years
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