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.

Normal Results

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:

• Dehydration
• Shock
• Peripheral vascular disease (PVD)
• Hypothermia

Risks

No risks are associated with this test.

Alternative Names

Nail blanch test; Capillary refill time

Update Date: 5/30/2012

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.