To prove that medical malpractice occurred, you must be able to show all of these things:
A doctor-patient relationship existed. You must show that you had a physician-patient relationship with the doctor you are suing -- this means you hired the doctor and the doctor agreed to be hired. For example, you can't sue a doctor you overheard giving advice at a cocktail party. If a doctor began seeing you and treating you, it is easy to prove a physician-patient relationship existed. Questions of whether or not the relationship exists most frequently arise where a consulting physician did not treat you directly.
The doctor was negligent. Just because you are unhappy with your treatment or results does not mean the doctor is liable for medical malpractice. The doctor must have been negligent in connection with your diagnosis or treatment. To sue for malpractice, you must be able to show that the doctor caused you harm in a way that a competent doctor, under the same circumstances, would not have. The doctor's care is not required to be the best possible, but simply "reasonably skillful and careful." Whether the doctor was reasonably skillful and careful is often at the heart of a medical malpractice claim. Almost all states require that the patient present a medical expert to discuss the appropriate medical standard of care and show how the defendant deviated from that standard.
The doctor's negligence caused the injury. Because many malpractice cases involve patients that were already sick or injured, there is often a question of whether what the doctor did, negligent or not, actually caused the harm. For example, if a patient dies after treatment for lung cancer, and the doctor did do something negligent, it could be hard to prove that the doctor's negligence caused the death rather than the cancer. The patient must show that it is "more likely than not" that the doctor's incompetence directly caused the injury. Usually, the patient must have a medical expert testify that the doctor's negligence caused the injury.
The injury led to specific damages. Even if it is clear that the doctor performed below the expected standards in his or her field, the patient can't sue for malpractice if the patient didn't suffer any harm. Here are examples of the types of harm patients can sue for:
additional medical bills, and
lost work and lost earning capacity.
A wide variety of situations can lead to a medical malpractice claim -- from a doctor leaving a sponge in a patient's stomach during an operation to failing to tell a patient that a prescribed drug might cause heart failure. Most medical malpractice claims fall into one of these categories:
Failure to diagnose. If a competent doctor would have discovered the patient's illness or made a different diagnosis, which in turn would have led to a better outcome than the one actually achieved, then the patient may have a viable medical malpractice claim.
Improper treatment. If a doctor treats the patient in a way that no other competent doctor would, the patient could have a medical malpractice claim. In a similar vein, it may also be malpractice if the doctor selects the appropriate treatment but administers it incompetently.
Failure to warn a patient of known risks. Doctors have a duty to warn patients of known risks of a procedure or course of treatment -- this is known as the duty of informed consent. If a patient, once properly informed of possible risks, would have elected not to go through with the procedure, the doctor may be liable for medical malpractice if the patient is injured by the procedure (in a way that the doctor should have warned could happen).