Good day Dr. Bill.


Question would be if I smoke a small half joint of marijuana on July 6 and got tested on July 17. Will it be positive?
Never smoked marijuana before and I am 5 feet 5, 155 pounds. Drinks water regularly and on Hydrochlorothiazide daily.

Best,
Nervous

Based on your description it should not be detectable in urine at that time span. THC and metabolites (cannabinoids) are metabolized much faster in infrequent and single use and/or the metabolite(s) left behind would not rise above the level of detection.

Based on your description it should not be detectable in urine at that time span. THC and metabolites (cannabinoids) are metabolized much faster in infrequent and single use and/or the metabolite(s) left behind would not rise above the level of detection.

Thank you for your fast response Dr. Bill.

You have been a very good source of information. But I was wondering? How long/days does a joint of marijuana become negative for a one time user on a 50ng and 20 ng cut off in laboratory testing?

There are multiple factors that relate to elimination time for any drug or substance. Population averages are just that and can be applied individually only at great risk of error.

That cleared, a one time user will usually be THC clear within a few hours to maybe 3 days. A consideration in rapid clearance is the amount of THC inhaled. Inexperienced smokers have not yet developed a personal method for titrating the dose, inhaling and holding the smoke. So between the experienced and inexperienced smoker there is a wide variance in amount of THC absorbed.

Second, most of an absorbed dose is eliminated in both groups but a small amount may secret in fatty tissue. That is a small portion of total dose... most is eliminated. The small amount of THC not metabolized attaches to the fatty tissue and releases slowly... therefore accumulates. There has to be a rather significant amount of stored THC in order for it to release in sufficient quantity to rise above the 50ng or even 20ng level. That also explains how one can test negative one day and positive the next.

Finally you use the term "joint of marijuana" as though it is a standardized unit of measurement. In fact the THC content in street-bought product may vary by 2000%. Of special note is that most of the timed elimination studies in the US used only 1.5 and 3.75% controlled growth cannabis. As a comparison seized marijuana now averages 9% THC.

It's necessary to compare a lot of different studies from different countries over a long period to even begin to get a picture of THC timing.

When I cite a few hours to 3 days it is wise to rely on the longest period. All of the factors mentioned above are unknown in relation to a given individual. At least to some extent this also relates to the mixed bag of information you run across not only on-line but in professional literature as well.

There are multiple factors that relate to elimination time for any drug or substance. Population averages are just that and can be applied individually only at great risk of error.

That cleared, a one time user will usually be THC clear within a few hours to maybe 3 days. A consideration in rapid clearance is the amount of THC inhaled. Inexperienced smokers have not yet developed a personal method for titrating the dose, inhaling and holding the smoke. So between the experienced and inexperienced smoker there is a wide variance in amount of THC absorbed.

Second, most of an absorbed dose is eliminated in both groups but a small amount may secret in fatty tissue. That is a small portion of total dose...most is eliminated. The small amount of THC not metabolized attaches to the fatty tissue and releases slowly...therefore accumulates. There has to be a rather significant amount of stored THC in order for it to release in sufficient quantity to rise above the 50ng or even 20ng level. That also explains how one can test negative one day and positive the next.

Finally you use the term "joint of marijuana" as though it is a standardized unit of measurement. In fact the THC content in street-bought product may vary by 2000%. Of special note is that most of the timed elimination studies in the US used only 1.5 and 3.75% controlled growth cannabis. As a comparison seized marijuana now averages 9% THC.

It's necessary to compare a lot of different studies from different countries over a long period of time to even begin to get a picture of THC timing.

When I cite a few hours to 3 days it is wise to rely on the longest period of time. All of the factors mentioned above are unknown in relation to a given individual. At least to some extent this also relates to the mixed bag of information you run across not only on-line but in professional literature as well.

Such a great explanation!

In summary, I should not be worried testing positive when smoking a joint of marijuana with a time span of 11 days between the time of smoke to the urine testing via Quest diagnostics. Hydration, Hydrochlorothiazide, coffee, factors , and first time use,are included in a 50 or 20 ng test cut off. I did my own research with the NIH, Paul Cary(toxicology), SAMSHA, Annals of Toxicology...

All these researches said I should not be worried. But, I don't know why if Dr. Bill100 says so. I feel a lot more at ease:)