An invasive procedure is a medical procedure that invades (enters) the body, usually by cutting or puncturing the skin or by inserting instruments into the body past the anus, past the back of the throat, or into the ear canal. As a rule, only a physician may perform an invasive procedure, but other health care professionals may perform certain invasive procedures if they are properly trained, such as a nurse preparing an intravenous line or giving a vaccination with a needle.

Some of these procedures often are designated a minimally invasive procedure. These are procedures that still must be performed by a physician as a rule, but are considered at least as safe as non-invasive procedures. These would include procedures such as injections, inserting a suppository, or performing a skin biopsy. These may generally be performed by a generally trained physician without any special precautions.

However, as a rule, the more invasive a procedure, the more likely it is that proper medical practice will require that it be performed by a medical specialist under special conditions. For example, open heart surgery must be performed by a board certified surgeon with a sub-speciality in cardiac surgery, in an operating room, with an anesthesiologist.

In addition, the requirements for informed consent usually increase with how invasive the procedure is, regardless of actual risk. For example, if a patient is unconscious with no medical proxy, physicians usually do not require permission to perform non-invasive or minimally invasive procedures, but must either obtain approval for invasive procedures or they must be part of a standard operating procedure for emergencies (such as inserting a tracheal tube to support a respirator).

When attempting to make a diagnosis, rather than performing a treatment, protocol usually demands that all non-invasive and minimally invasive procedures be ruled out before proceeding with an invasive procedure. This general rule exists because the risk of an invasive procedure is often greater than the risk of the possible underlying conditions. For example, exploratory surgery is usually a last resort in the diagnostic process as it can be fatal in and of itself.

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