The urine serves to get rid of chemicals in your body, okay. That's probably the main group. What you are looking at, the urine really doesn't count as far as the interpreting it. The Delta-9 in the blood tells you because Delta-9 in the blood only hangs around for a short period of time, like maybe two hours. It has a relatively short half life. It is in, produces its affects, the affects last longer in the presence of the Delta-9, but when you have it in there it goes to acute use, that's within a couple of hours.