There are no tests in particular that are used specifically for schizophrenia, but tests like MRI or CT scans or blood tests may be used to make sure that the person does not have symptoms of psychosis because of organic problems in the brain, and to make sure that there is no physical illness as the cause. There are also come checklists and rating scales that may be used to assess the severity or presence of schizophrenia symptoms and to assess whether there are positive or negative symptoms in the person.