Does the lab know if the urine sample is artificial?

Yes

Yes, plus the temperature will be all wrong.

Drank 1 beer at 11 am, tested next day at 5 pm, will I pass?

Test positive 29 hrs after one 12 oz beer, what are the odds?

Does it really matter... since you failed. To many unknown variables for even a statistics wiz to calculate the odds.

Just don't drink.. then you will pass with the REAL sample.

They will let you know.

They can tell if it's fake. They can tell if it's diluted. They can tell if you got it from someone else and brought it in (will be the wrong temperature). You need to just not do anything to make it test positive, and if you already have and are going to fail, you need to face the music.

Pay attention to what's really important. If you miss a visit with a child because of a failed test, or loose a job, or just don't get a job you've applied to, or violate probation - well, that all sucks temporarily but with sobriety, you'll sort it out after you face the temporary consequences.

More important is that you are struggling with addiction. If you test positive, own that result and use it to improve your life. If you have to go in front a judge and he points out that you failed, you respond, "you're honor - I need help. Can you help me?" Stop trying to game the system and solve the problem by addressing the behavior.

God bless.