Cold Stimulation Test

Why this test may be ordered

• You have symptoms of Raynaud phenomenon, such as fingers or toes turning white or blue, feeling numb or painful, or taking a long time to warm up after exposure to cold or stress.
• Your provider wants to help confirm a diagnosis of Raynaud phenomenon after a physical exam and review of your medical history.

Preparation and collection

You don't need any special preparations for a cold stimulation test.

A small device that measures temperature will be taped to your fingers. Your provider will record the temperature. You will then place your hands into an ice water bath for 20 seconds. After removing them, your provider will record your finger temperature every five minutes for up to 20 minutes, or until your temperature returns to the same as it was before the ice water bath.

You may feel some discomfort while your hands are in the ice water. There are no other known risks from this test.

Understanding results

Your provider will compare your finger temperature recovery time to the normal temperature measured before the ice water bath. Results help determine whether you have Raynaud phenomenon and, if so, whether it may be primary or secondary.

• Normal (recovery within 20 minutes): Your finger temperature returns to normal within less than 20 minutes after the ice water bath. This suggests you probably do not have Raynaud phenomenon. Limitation: Interpretation should be done by your healthcare provider based on your full clinical picture. Next step: If your symptoms are mild and you are under 35, primary Raynaud phenomenon is likely. Lifestyle changes are often sufficient.
• Abnormal (recovery time ≥ 20 minutes, suggests Raynaud phenomenon): Your finger temperature takes 20 minutes or more to return to normal after the ice water bath. This probably means you have Raynaud phenomenon. If symptoms are severe or you are age 35 or older, you may have secondary Raynaud phenomenon. Limitation: Interpretation should be done by your healthcare provider based on your full clinical picture. Next step: Your provider may evaluate for secondary causes (e.g., autoimmune disease, connective tissue disorders) especially if you are age 35 or older or have severe symptoms. Additional tests (nailfold capillaroscopy, blood tests) may be ordered.

• The test is used to help confirm a diagnosis of Raynaud phenomenon after a physical exam and review of symptoms and medical history.
• A recovery time of 20 minutes or more probably means you have Raynaud phenomenon, but the result is not a definitive diagnosis by itself.
• If you have severe symptoms and/or are age 35 or older, you may have secondary Raynaud phenomenon, which requires further testing to identify the underlying cause (e.g., nailfold capillaroscopy, blood tests for immune system disorders).
• The test does not distinguish between primary and secondary Raynaud phenomenon on its own.

What to do next

If your results suggest Raynaud phenomenon, your provider may recommend lifestyle changes such as dressing warmly, avoiding cold, stress, smoking, and caffeine. For more severe cases, medications to help open blood vessels or a procedure to destroy nerves that trigger vessel narrowing may be considered. Talk to your provider about your specific results and follow-up plan.

• Do you have symptoms such as fingers or toes turning white or blue, feeling numb or painful, or taking a long time to warm up after exposure to cold or stress?
• Have you experienced these symptoms after exposure to cold or emotional stress, or after smoking or vaping?
• Do you have any other medical conditions (e.g., lupus, scleroderma, carpal tunnel syndrome) or take medications that could affect blood vessels?
• What is your age? (Age may help distinguish primary vs. secondary Raynaud phenomenon.)

Evidence source

U.S. National Library of Medicine: Cold Stimulation Test