I've always thought you need a requisition from a doctor, you can't just go pay for something, that's the only way I've seen it done. At least I've never seen services like the OP advertised, that's why I was stricken by it.

(Happy to be corrected)

Hm, over here you need a prescription for medication, but you can do whatever test you want to pay for. I don't know about Canada, though.