Capillary nail refill test

What is a Capillary Nail Refill Test?

A capillary nail refill test is a simple procedure used to evaluate the circulation of blood in a patient's extremities, specifically in the nail beds of the fingers or toes. This non-invasive test is used to help diagnose peripheral vascular diseases, impaired microcirculation, and other vascular diseases that prevent blood flow from flowing to the tips of the patient's fingers and toes.

Preparation and Procedure

The patient and practitioner generally walk into a room and the practitioner will ask the patient to remove their shoes and socks and place their feet in a warm bath of water. The practitioner will then gently press on the nailbed with the index finger and observe the patient's nail for any type of reactivity. After the patient's nailbed has been pressed, a timer is set to measure the time it takes for the nailbed to refill with blood.

Types of Capillary Nail Refill Test

• Direct Capillary Refill Test – This is the most common type of test and is performed by pressing an area of the patient's fingernailbed. It typically takes one to two seconds for the nailbed to refill with blood.
• Indirect Capillary Refill Test – This type of test measures the time it takes for the patient's feet or hands to turn pink once pressure is released from the nailbed. The time is recorded in seconds, and a lower than normal time signals an impaired circulation.
• Capillary Refill Time Test – This is the most accurate of the three tests and uses an instrument specifically designed for measuring the time it takes for the patient's nailbed to fill with blood. The time is recorded in milliseconds, and lower than normal readings indicate an impaired microcirculation.

Risks and Contraindications

Capillary nail refill tests are generally considered safe, low-risk tests with no known contraindications. However, if a patient has impaired circulation due to a vascular disease, additional tests may be necessary to diagnose the condition.

Why and When Is the Test Done?

A capillary nail refill test is done to assess the circulation of blood in a person's extremities, which can help diagnose or rule out certain vascular diseases, such as peripheral vascular disease or impaired microcirculation. An impaired circulation can also be indicative of other conditions, such as diabetes, peripheral neuropathy, and thyroid disease. The test is usually done during a physical examination, but can also be done after a certain procedure or illness.