Grey zone. You can't sue them because they haven't tried all the experimental treatments known. You probably can't even sue them if it is a misdiagnosis, unless

Grey zone. You can't sue them because they haven't tried all the experimental treatments known. You probably can't even sue them if it is a misdiagnosis, unless it was egregious. The police equivalent is that you don't expect them to be able to intercept every bullet fired everywhere. Particular if it is a the risk of their own lives.