Capillary refill time is a quick, reliable method for detecting changes in blood flow that can lead to shock. Healthcare providers apply pressure to a finger to empty the blood vessels. After releasing the pressure, they time how long it takes them to refill with oxygen-rich blood.
Capillary refill time assesses blood circulation in your arms and legs (peripheral perfusion). It detects shock in people with life-threatening illnesses or injuries.
Capillaries are tiny blood vessels. They connect arteries to veins, supporting the flow of oxygen throughout your body.
Shock is a dangerous condition that occurs when there’s a sudden decrease in blood flow. If this happens, your organs aren’t receiving the oxygen they need to function. Emergency treatment is necessary to help you survive.
Shock comes on suddenly, leaving little time for lab tests or imaging studies. Capillary refill time is a quick method for detecting changes in peripheral perfusion that can lead to shock.
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You may need this test if you have or are at risk for shock due to:
Healthcare providers perform a capillary refill test when a person becomes medically unstable.
They may experience:
Capillary refill time is also a method for assessing whether therapies to prevent or treat shock are working.
Healthcare providers assess peripheral perfusion by:
On rare occasions, a finger or toe might not be the best place to perform a capillary refill test. When this happens, healthcare providers use skin near your breastbone (sternum).
A capillary refill test using your sternum may be necessary for people:
In a healthy person, a normal capillary refill should only take a few seconds:
If you’re in shock or medically unstable, a normal capillary refill time doesn’t mean you aren’t sick. It lets healthcare providers know that the problem doesn’t have to do with your circulatory system. They’ll continue assessing you to pinpoint the source so you can receive the treatments you need.
If results are outside the normal range, healthcare providers may use other rapid testing methods to confirm the cause. These tests also help determine how severe the issue is.
Other methods of testing peripheral perfusion include:
Capillary refill time is one of many tests that assess the status of people who are at risk for shock. Real-time monitoring provides additional information to enable quick decision-making during an emergency.
Monitoring includes checking your:
You’ll likely need to start treatment right away. The treatment that’s right for you depends on what’s causing symptoms and how severe they are.
Your care may include:
A note from Cleveland Clinic
Capillary refill time assesses peripheral perfusion in people at risk for shock. It enables healthcare providers to check for sudden blood flow decrease after a severe illness or injury. If the capillaries in your finger or toe are slow to refill, emergency treatments can save your life.
Last reviewed by a Cleveland Clinic medical professional on 06/27/2022.
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