Yes, nothing will be there, they will not be found, do not worry, but even if you really need to do a test, then a pancake you have to stupidly eat a jar of yellow vitamins in 20 minutes and everything will show nothing if you piss into a jar
The polyclinic does not have the right to test you for drugs. For this there are drug treatment hospitals. Anyway, in my opinion, it violates human rights, it is everyone's business to kill or not.
To determine drugs, special reagents and special equipment are needed. This is not used in ordinary analyzes, so they will not be able to accidentally find drugs in the polyclinic.
If you purposefully passed tests for drugs and traces of them were found, then you will be added to the database by a narcologist, treatment will be recommended. This will lead to problems with obtaining a driver's license, weapons, adoption. There will also be problems with finding employment in official jobs.