Capillary Refill Time

What is capillary refill time?

Capillary refill time assesses blood circulation in your arms and legs (peripheral perfusion). It detects shock in people with life-threatening illnesses or injuries.

What are capillaries?

Capillaries are tiny blood vessels. They connect arteries to veins, supporting the flow of oxygen throughout your body.

What is shock?

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.

Who needs a capillary refill test?

You may need this test if you have or are at risk for shock due to:

• Anaphylaxis.
• Dehydration.
• Hemorrhage.
• Hyperthermia (high body temperature).
• Hypothermia (low body temperature).
• Severe burns.

When is a capillary refill test performed?

Healthcare providers perform a capillary refill test when a person becomes medically unstable.

They may experience:

• Altered mental state, which may include confusion or unusual behavior.
• Cold hands, arms, legs or feet.
• Dangerously low or high vital signs (blood pressure, pulse, breathing rate and temperature).
• Loss of consciousness.

Are there other reasons I may need this test?

Capillary refill time is also a method for assessing whether therapies to prevent or treat shock are working.

What happens during a capillary refill time test?

Healthcare providers assess peripheral perfusion by:

• Elevating one hand or foot above your heart.
• Applying pressure to one finger or toe for up to 10 seconds. Pressure makes the finger or toe appear pale in color.
• Release pressure and time how long it takes the skin to return to the same color as nearby tissue. This color change is due to oxygen-rich blood filling up empty capillaries.

Is the test always conducted using a finger or toe?

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:

• Whose body temperatures are below average due to hypothermia.
• Who arrive at the hospital cold due to winter weather.

What’s considered a normal result?

In a healthy person, a normal capillary refill should only take a few seconds:

• Newborns could take as little as two seconds.
• Adults refill in about three seconds.
• Older adults often take more than three seconds.

What if my capillary refill time is within the normal range?

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.

What if my results are abnormal?

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:

• Pulse oximetry measures your blood oxygen level.
• Laser Doppler flowmetry combines laser beams with sound waves to measure the force of blood through veins and arteries.
• Near-infrared spectroscopy uses rays of light to assess oxygen levels in tissue.

Is capillary refill time the only test I’ll need?

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:

• Pulse rate.
• Blood pressure.
• Level of consciousness.
• Urine output.

What happens after it’s determined shock symptoms are due to a circulatory system issue?

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:

• Blood transfusion.
• Breathing tube (intubation).
• IV fluids.
• Medications, such as steroids or antibiotics.
• Rapid body cooling.
• Supplemental oxygen.