How is carpal tunnel syndrome diagnosed?

Carpal tunnel syndrome is usually diagnosed from your history and a hand examination, and a nerve test is added only when the picture is unclear. The NHS says the condition can usually be diagnosed by asking about your symptoms and checking your hand ¹. The American Academy of Orthopaedic Surgeons says that in many cases no further testing is needed ².

The history and the hand exam come first

The first appointment is mostly questions. A clinician asks which fingers go numb, whether the symptoms wake you, and which tasks bring them on, such as typing, phone use or gripping. The answers set the direction of the examination, because the pattern of numbness separates carpal tunnel from neck and elbow problems.

The examination then checks sensation, strength in the hand and wrist, and reflexes, and it repeats the movements that reproduce your symptoms. The bedside tests below are the usual ones.

Bedside tests check the wrist and median nerve

Several provocative tests are used. Each one loads the carpal tunnel in a different way and is positive if it brings on the tingling or numbness you describe. The three most often named are Phalen's test, Tinel's sign and Durkan's test. Clinicians also use a reverse Phalen's test and a combination of wrist flexion with carpal compression.

The OrthoInfo patient guide describes Phalen's test as bending and holding the wrists in a flexed position to check for numbness or tingling. Tinel's sign taps along the median nerve on the palm side of the wrist and checks for tingling in the fingers. The table gives the accuracy figures that studies report, which differ from one study to the next.

The two studies that report Phalen's test disagree, and the gap is large. Both are reported here so you can see how much the figures move between studies. A test that is sensitive picks up most people who have the condition, but a low specificity means many people without it also test positive. The Durkan figures show that trade-off: the test catches most cases but gives many false alarms.

No single test settles the diagnosis

A 2023 meta-analysis concluded that, without an accepted gold standard, a combination of examinations and the history should guide the diagnosis ⁶. That is the reason clinicians weigh the symptoms, the examination and any nerve results together, rather than trusting one positive or negative test.

Nerve tests confirm the diagnosis when the picture is unclear

If the examination leaves doubt, the next step is usually a nerve conduction test, which measures how well the nerve carries its electrical signal across the wrist. The American Association of Electrodiagnostic Medicine's practice parameter says that median nerve conduction studies confirm a clinical diagnosis with sensitivity above 85 percent and specificity of 95 percent ⁷. The figures describe how well the test confirms a diagnosis a clinician already suspects, not how well it finds carpal tunnel in people with no symptoms.

If a health professional is not sure, the NHS says they may refer you to hospital for a nerve test, or for a scan such as an ultrasound or MRI, according to its carpal tunnel syndrome guidance ⁸.

A positive nerve test is not a diagnosis on its own. In a Swedish population study, 18.4 percent of people with no reported symptoms had abnormal median nerve conduction tests ⁹. An abnormal result has to match the symptoms and the examination before it means carpal tunnel.

What it means when the tests disagree

If the symptoms are present but the examination and nerve test are normal, the cause may be something else. Pain at the base of the thumb or a locking finger, for example, is a different problem, and the hand and wrist pain guide compares them. If the arm symptoms start in the neck, the neck needs examining too, as set out in carpal tunnel or pinched nerve in the neck.

What to do before and after the appointment

1. Keep a short record of the fingers affected, when the numbness happens, and the tasks that bring it on. Bring it to the appointment.
2. Ask what each test is for and what result would change the plan. A clinician who explains that makes the follow-up easier.
3. Ask whether a nerve test is needed if the examination was clear, or if you are not sure what the result means.
4. See a doctor sooner if the numbness persists, the hand weakens, or the neck and arm symptoms come together.
5. Read about treatment once the diagnosis is clear. The carpal tunnel treatment guide covers splints, injections and surgery, and the choice depends on the confirmed diagnosis.

This is general information, not a diagnosis. For the wider picture, see the carpal tunnel syndrome guide and our accessibility and health overview. The nerve that the tests examine is the median nerve.