Capillary nail refill test
The capillary nail refill test is a quick test performed on the nail beds to monitor dehydration and the amount of blood flow to tissue.
Nail blanch test; Capillary refill time
How the test is performed
Pressure is applied to the nail bed until it turns white, indicating that the blood has been forced from the tissue. This is called blanching. Once the tissue has blanched, pressure is removed.
While the patient holds their hand above their heart, the health care provider measures 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
Remove colored nail polish before this test.
How the test will feel
There will be minor pressure to the bed of your nail, which should not cause discomfort.
Why the test is performed
Tissues need oxygen to survive. Oxygen is carried to various parts of the body by the blood (vascular) system.
This test measures how well the vascular system works in your hands and feet -- the parts of your body that are farthest from the heart.
If there is good blood flow to the nail bed, a pink color should return in less than 2 seconds after pressure is removed.
What abnormal results mean
Blanch times that are greater than 2 seconds may indicate:
What the risks are
No risks are associated with this test.
Reviewed By: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.