Tell them before you take the test. How did you get IV Ketamine and IV Dilaudid? Neither is legally available outpatient unless prescribed by a physician FOR you while in hospital or direct medical care.
And I would suggest that you should prepare yourself for dismissal/discharge.
I think you already know this and are hoping someone can offer you an excuse/reassurance that the dr won’t find out or will overlook it- I don’t think any dr would overlook obtaining medications illegally or self medicating/IV drug misuse- at least I would hope not. To do so is dangerous, not only for you but for any other patient he treats.
Self medicating, misusing, abusing, obtaining medications NOT prescribed to you is dangerous and could have resulted in your death.
There is no I only tried it once to see what it was like as a valid excuse- there isn’t one.
I know this sounds harsh- and I won’t apologize for that. Obtaining those drugs, using them was dangerous, illegal, and could have caused as overdose or death.