I guess when you are doing your own investigation, you must be a lab technician. Anyways, as far as my knowledge goes about testing for substance use, there are very less number of hospitals including the hi fi corporate hospitals who are well equipped to even screen patients for the drugs of abuse. The screening test which is done is very unlikely to reveal the value of 300. The test that you are talking may be the actual drug test
where the values may be reveled which i am not sure at this point of time. I wonder form where you would get access to these kits. But the Methamphetamine
you are talking may be secreted in the urine for up to a day or even a few days (up to 7 days). When this is the situation, it is very unlikely that you will be getting a concrete answer for being a passive smoker for methamphetamine and that the levels would be 300 (Units - Not known). And good luck with whatever you are up to. Please enrich us with your experience in this.