In general, you can trust a psychiatrist to be real as these are medical doctors and governments are usually hot on policing those. Usually.
Medicine and medical tests are the province of medical doctors. Of the mental health practitioners, only psychiatrists, medical doctors who specialise in mental health, do these.
Psychologists, therapists, counsellors and so on don't them
So, if you're asked for a urine test or told to buy vitamins or whatever, and you are not talking to a psychiatrist - run!
Governments can be lax about who's calling themselves a psychologist. But universities will out fakes who claim to be alumni
Everyone knows about the fakes and so we're careful to state on our business cards and web sites exactly what we studied and where
If you don't see the name of a university, run
If you don't see the exact qualification, run
Money. Practitioners tend to be cheap compared to crooks.