Why don't you buy a home drug test in a pharmacy or deartment store or online and test your first piss of the morning, which will be your dirtiest urine. If you pass that you should be able to pass a 50 ng/ml cutoff lab test. There are also methods to dilute your urine but to dilute it enough to pass without coming back negative dilute. It involves some specific measurements of volume as well as a few supplements to add "the good stuff" back to your urine.