BJCC
You do need to talk to a Doctor.
He will say:
Alcohol when consumed, empties from the stomach into the gut, to the blood, is then broken down by the Liver and excreted in urine into the bladder. Urine contains what is excreted from the body, and does not reflect what is currently in the blood.
The Liver breaks down alcohol at a steady rate of about one standard unit per hour.
Hence, if you take one standard drink, wait one hour, take a pee then you will have no alcohol in your body.
If you choose not to take a pee, but wait a couple of hours and are then tested, then your breathe and blood will test negative but your urine positive and you are guilty of an offence.
Your crime?
Failing to take a pee!
I rest my case.