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Will Marijuana show up in a hair test after a month of usage?

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Posted on Mon, 25 May 2015
Question: I have smoked marijuana on four separate occasions over the last four months. Will I more likely pass or fail a hair test coming up this week?
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Answered by Dr. Vivek Chail (19 minutes later)
Brief Answer:
Most likely you will pass the marijuana hair test this week

Detailed Answer:
Hi XXXX,
Thanks for writing in to us.

I have read through your query in detail.
Please find my observations below.

1. Hair test for marijuana shows positive results in those who take it regularly. Almost 85 percent of those who smoke marijuana daily have a positive hair test. Only half of occasional users who take it at least once a week have a positive test.

2. You have smoked marijuana only on 4 occasions in last four months therefore the possibility of having a positive test result is least likely.

Hope this answers your question. Please feel free to correct any oversight in my interpretation of your problems and discuss them in detail as per your requirements.

Hope your query is answered.
Do write back if you have any doubts.

Regards,
Dr.Vivek
Above answer was peer-reviewed by : Dr. Chakravarthy Mazumdar
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Follow up: Dr. Vivek Chail (4 minutes later)
Thank you so much. Now, do every single one of your hair strands have the THC I them or only some of them?

This means it does not go back three months after last use for an occasional user, right?
doctor
Answered by Dr. Vivek Chail (45 minutes later)
Brief Answer:
The recent 1.5 inches hair length is tested

Detailed Answer:
Hi XXXX,
Thanks for writing back with an update.

1. When doing the hair test, the recent 1.5 inches hair is tested for the presence of breakdown products of marijuana. This might be found in all hairs in an individual and not restricted to a particular distribution. However some hairs might have a higher concentration and therefore appear positive in the test.

2. For research purposes, an occasional user has been classified as one who smokes 1 to 5 times a week and a daily user smokes it every day. If someone is a consistently occasional user then it might be found positive even after 3 months of cessation.

3. Your pattern of intake is less than an occasional user therefore there is no serious concern.

Hope your query is answered.
Do write back if you have any doubts.

Regards,
Dr.Vivek
Above answer was peer-reviewed by : Dr. Chakravarthy Mazumdar
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Answered by
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Dr. Vivek Chail

Radiologist

Practicing since :2002

Answered : 6840 Questions

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Will Marijuana show up in a hair test after a month of usage?

Brief Answer: Most likely you will pass the marijuana hair test this week Detailed Answer: Hi XXXX, Thanks for writing in to us. I have read through your query in detail. Please find my observations below. 1. Hair test for marijuana shows positive results in those who take it regularly. Almost 85 percent of those who smoke marijuana daily have a positive hair test. Only half of occasional users who take it at least once a week have a positive test. 2. You have smoked marijuana only on 4 occasions in last four months therefore the possibility of having a positive test result is least likely. Hope this answers your question. Please feel free to correct any oversight in my interpretation of your problems and discuss them in detail as per your requirements. Hope your query is answered. Do write back if you have any doubts. Regards, Dr.Vivek