Capillary nail refill test
Nail blanch test; Capillary refill timeThe capillary nail refill test is a quick test done on the nail beds. It is used to monitor dehydration and the amount of blood flow to tissue.
Dehydration
Dehydration occurs when your body does not have as much water and fluids as it needs. Dehydration can be mild, moderate, or severe, based on how much...
Read Article Now Book Mark ArticleHow the Test is Performed
Pressure is applied to the nail bed until it turns white. This indicates that the blood has been forced from the tissue under the nail. It is called blanching. Once the tissue has blanched, pressure is removed.
While the person holds their hand above their heart, the health care provider measures the time it takes for blood to return to the tissue. Return of blood is indicated by the nail turning back to a pink color.
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. This 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
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Hypothermia
Hypothermia
Hypothermia is dangerously low body temperature, below 95°F (35°C).
Read Article Now Book Mark Article - Low blood pressure
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Peripheral vascular disease (PVD)
Peripheral vascular disease
Peripheral artery disease (PAD) is a condition of the blood vessels that supply the legs and feet. It occurs due to narrowing of the arteries in the...
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Shock
Shock
Shock is a life-threatening condition that occurs when the body is not getting enough blood flow. Lack of blood flow means the cells and organs do n...
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References
McGrath JL, Bachmann DJ. Vital signs measurement. In: Roberts JR, Custalow CB, Thomsen TW, eds. Roberts and Hedges' Clinical Procedures in Emergency Medicine and Acute Care. 7th ed. Philadelphia, PA: Elsevier; 2019:chap 1.
Schoener B, Wagner MJ. Hand injuries. In: Walls RM, ed. Rosen's Emergency Medicine: Concepts and Clinical Practice. 10th ed. Philadelphia, PA: Elsevier; 2023:chap 42.
Swartz MH. The peripheral vascular system. In: Swartz MH, ed. Textbook of Physical Diagnosis: History and Examination. 8th ed. Philadelphia, PA: Elsevier; 2021:chap 15.
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Nail blanch test - illustration
The nail blanch test, also called the capillary nail refill test, is performed on the nail beds as an indicator of tissue perfusion (the amount of blood flow to tissue) and dehydration.
Nail blanch test
illustration
Review Date: 6/20/2023
Reviewed By: Jacob Berman, MD, MPH, Clinical Assistant Professor of Medicine, Division of General Internal Medicine, University of Washington School of Medicine, Seattle, WA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.