How is carpal tunnel syndrome diagnosed?
There are a number of ways in which carpal tunnel syndrome can be diagnosed, including examination and testing.
Examination of the wrist
Your doctor will examine your hand and wrist to try to confirm the diagnosis and to assess how severe it is. If your wrist is swollen due to arthritis or an inflamed tendon, this could be the cause of your symptoms. If you’ve had the condition for some time, there may be signs of muscle wasting at the base of the thumb. If the problem is severe, the thumb, index and middle fingers may be insensitive (numb) to either a gentle touch or a pin prick.
Your doctor may also:
- tap over the median nerve on the palm side of your wrist (Tinel’s test)
- ask you to bend your palm towards your forearm for up to a minute (Phalen’s test)
These tests can help to confirm carpal tunnel syndrome, though they aren't fully reliable so you may also have one of the tests described below.
Sometimes the condition is mistaken for something else. For example, pressure on nerves in the neck due to disc problems or arthritis can cause similar symptoms. A nerve conduction test may help if there’s any doubt about the diagnosis or to see how severe the compression of the nerve is. This test can be done in several ways but one common measurement is made by stimulating a finger with a small electric current while recording the response of the median nerve at the wrist with a pair of electrodes attached to the skin. When the nerve is impaired, the speed of conduction between the finger and the wrist is slower.