When a patient discovers that a doctor failed to diagnose a serious health condition on time- which led to disastrous consequences for the patient-whether in the hospital or in the doctor’s chamber, the patient has the right to sue the doctor. The key consideration in a medical malpractice lawsuit related to misdiagnosis is whether there is an identifiable lack of qualification on the part of the doctor. Another angle may be “medical negligence.” which can lead to more serious legal proceedings against the doctor.