Can I have one beer tonight sat. and pass EtG on Monday morning

There will be traces in your system, it is said approximately 3 days or 72 hours for alcohol to completely dissipate your system,prior to that time there will be traces and maybe small amount. I'm not sure the amount needed for them to declare you clean or free of alcohol as there is a certain amount that is considered normal.

The best way to "pass an EtG test" is to avoid all exposure to alcohol, and if you are being tested for EtG, you should not be drinking anyway.

P.S. Welcome to the site,

Sarah