What are examples of medical malpractice bycommssion?

I think you mean by omission. Medical malpractice is defined as professional negligence by act or omission by a medical professional. This would include a doctor who fails to catch signs of cancer; a nurse practitioner who misdiagnoses an ailment or a nurse who does not respond to troublesome vital signs of a patient.
There is a link on fail to diagnose that goes into more detail below.