Contact and Hours:

1580 Valencia Street Suite 703
San Francisco, CA 94110
Phone: 415-642-0707
Fax: 415-648-7988

Monday through Thursday:
7:30 am to 4:30 pm

Friday 8:00 am to 3:00 pm

Closed Saturday and


Electrodiagnostic medicine is the study of diseases of nerves and muscles. Your doctor has recommended an EMG test to see if your muscles and nerves are working right and assist in finding the correct diagnosis for your problem. You can have problems in only one part of your body or throughout your body. The results of the tests will help your doctor decide what is wrong and how it can be treated.

Who does the testing?
The American Association of Neuromuscular & Electrodiagnostic Medicine’s policy is that an appropriately trained doctor should do all needle EMG testing. A trained assistant or technologist under a doctor’s supervision can also do nerve conduction studies. 

Why am I being sent to the EMG Lab for tests?
You are being sent to the electromyography (EMG) lab because you have numbness, tingling, pain, weakness, or muscle cramping. Some of the tests that the EMG doctor may use to diagnose your symptoms are nerve conduction studies (NCSs), needle EMG, and evoked potentials. The EMG doctor will examine you to decide which tests to do.

Nerve Conduction Studies
NCSs show how well the body’s electrical signals are traveling through a nerve. This is done by applying small electrical shocks to the nerve and recording how the nerve functions. These shocks cause a quick, mild, tingling feeling in the distribution of the nerve. The doctor may need to test several nerves.

Needle EMG (Electromyography)
For this part of the test, a small, thin needle is put in several muscles to see if there are any problems. A new needle is used for each patient and it is thrown away after the test. There may be a small amount of pain when the needle is put in. The doctor tests only the muscles necessary to decide what is wrong. The doctor will look at and listen to the electrical signals that travel from the needle to the EMG machine. The doctor then uses his medical knowledge to figure out what could be causing your problem.
The tests usually take between 20 to 90 minutes. You can do any of your normal activities, like eating, driving, and exercising, before and after the tests. There are no lasting side effects.

How should I prepare for the tests?
Tell the EMG doctor if you are taking aspirin, blood thinners (like Coumadin®), have a pacemaker, or have hemophilia. Take a bath or shower to remove oil from your skin. Do not use body lotion on the day of the test. If you have myasthenia gravis, ask your EMG doctor if you should take any medications before the test.

When will I know the test results?
The EMG doctor will discuss your test results with you or send them to your regular doctor. After the exam, check with the doctor who referred you to the lab for the next step in your care.