EMG stands for electromyography, which is a test of the function of the muscles in the body. An EMG test is almost always performed along with a test of the nerves, known as nerve conduction studies (NCS). Together, EMG and NCS are called electrodiagnostics.
Electrodiagnostics can be thought of as a “stethoscope for the nerves”. When a doctor wants to evaluate the lungs, they often take a picture of the lungs, with an x-ray. But as most people have experienced, the doctor usually wants to hear how the air is moving through the lungs, so they listen with a stethoscope as well. Similarly, electrodiagnosis allows the doctor to see, and even hear, the flow of electricity through the nerves. Just like a stethoscope complements and adds extra information to an x-ray of the lungs, electrodiagnostic testing compliments and adds extra information to other tests, such as MRI and x-ray. This is why your doctor will often order electrodiagnostic testing in addition to an MRI or x-ray.
The electrodiagnostic test itself takes anywhere from 20 to 45 minutes, and most of that time, the doctor is working with the equipment, not actually examining you. Although you will be in the room with the doctor the whole time, only a small fraction of the test actually involves the doctor directly examining you. After the test, the doctor usually can give you a rough idea of the results immediately. It takes about a day for a formal report to be generated. So generally, by the next day, you can contact the doctor who ordered the test to find out any results.