The short answer is not necessarily.
That said, some mistakes in the practice of medicine are the result of negligence, either on the part of the staff, nurses, doctors and technicians or of the care facility itself. In fact, negligence is the third leading cause of death in the United States. U.S. News & World Report reported this May that an estimated 250,000 people die each year due to medical errors. So this is not an issue to be taken lightly.
The question of medical malpractice relates almost exclusively to negligence. There is an expected standard of care that patients are to receive and when that standard is not met you may have a case.
In a recent case a woman won a $6 million dollar settlement when, due to mixed up files, her appendix was erroneously and unnecessarily removed. She suffered long term effects of the operation including nerve damage.
There is however a statute of limitations for medical malpractice. Here in New York the time limit is 30 months. This is not a hard and fast rule however.
If a patient, for example, visits her doctor complaining of an abdominal lump and the doctor does a minimal physical exam and sends the patient home telling her it is most likely fibroids and not worry about it and then 32 months later a large cancerous uterine tumor is found, the patient may certainly have a case.
There may be contributing factors which influence the statute of limitations, such as if the patient experienced other symptoms or pain in that 30 month time period which she ignored. Generally speaking the statute of limitations then may not apply because she did nothing when she had new pain and symptoms.
Most doctors, nurses and care facility staff work diligently, and provide at times heroic, life-saving work. These professionals most likely entered the profession to help people and they are committed to improving healthcare and the health of their patients. However when egregious mistakes are made that indelibly and negatively affect a patient, those who are negligent, including the care facility, need to be held accountable.