When you are asked to submit to drug testing there are certain terms and phrases that you should become familiar with.  When you are trying to pass a urine test one of the phrases that you will encounter is the cutoff levels for certain drugs.  In marijuana urine tests the standard cutoff level is fifty nanograms per milliliter.  A nanogram is one billionth of a gram.  The typical urine sample should be approximately 2 ounces of urine.  This equals out to about fifty nine milliliters.  So there is a good chance you will test positive a few days after taking just a couple of puffs off of a joint.

It does take some time for the THC levels to taper off in your urine.  These cutoff levels were established due to testing results known as false positives.  There are certain substances that will cause your test results to come up positive for marijuana even if you have never touched the stuff.  Common pain relievers like Aleve, Bayer aspirin, Excedrin and even if you have liver disease it can come up as a false positive for THC but in levels lower than the 50ng/ml.  This is why these levels were established so that innocent people could not be judged as positive.  Anything over the 50ng/ml would be viewed as a positive result for marijuana.

Now if you decide to dilute your sample by drinking a lot of water, the testing facility may lower the cutoff level to 15ng/ml to compensate for the dilution or they could just fail you for dilution or make you retest.  Your typical home test will have a pass/fail cutoff level of 50ng/ml to be in accordance with industry standards so it would be wise to conduct an instant drug test at home before you go to submit your sample to determine whether or not you would need to do a total body cleanse or to use a detox drink to pass your urine test.