If my girlfriend drinks a 12 pack of 5.25% of beer on a friday night from 7pm to 3 am and doesn't drink anymore . By the time monday at 9am comes will she pass a pee test?

Alcohol is not illegal, finding it in a Pee test would not effect employment or other circumstances. Usually alcohol is as Jewels states, measured by breath, but it can also be measured by a blood test, because pee tests are not accurate for blood alcohol level.