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Capillary nail refill test

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Illustrations

Nail blanch test
Nail blanch test

Alternative names    Return to top

Nail blanch test; Capillary refill time; CRT

Definition    Return to top

This quick test is performed on the nail beds o monitor tissue perfusion (the amount of blood flow to tissue) and dehydration.

How the test is performed    Return to top

Pressure is applied to the nail bed until it turns white, indicating that the blood has been forced from the tissue (blanched). Once the tissue has blanched, pressure is removed.

The health care provider will measure the time it takes for blood to return to the tissue, indicated by a pink color returning to the nail.

How to prepare for the test    Return to top

No preparation is necessary for the test.

How the test will feel    Return to top

There will be minor pressure to the bed of your nail but it should not cause discomfort.

Why the test is performed    Return to top

Oxygen, which is critical to the survival of tissue, is carried to various parts of the body by the blood (vascular) system. This test measures how well the vascular system is functioning in your extremities. If you are dehydrated, or tissue perfusion is blocked by other means, this quick test can alert you or your health care provider that care needs to be taken to restore normal vascular flow.

Normal Values    Return to top

If there is good perfusion to the nail bed, a pink color should return in less than 2 seconds after blanching.

What abnormal results mean    Return to top

Blanch times that are greater than 2 seconds may indicate:

What the risks are    Return to top

No risks are associated with this test.

Update Date: 8/18/2003

Updated by: Daniel Levy, M.D., Ph.D., Infectious Diseases, Greater Baltimore Medical Center, Baltimore, MD. Review provided by VeriMed Healthcare Network.

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