Capillary refill is the rate at which blood refills empty capillaries. It can be measured by holding a hand higher than heart-level (prevents venous reflux), pressing the soft pad of a finger or toe until it turns white, and taking note of the time needed for the color to return once pressure is released. Normal refill time is less than 2 seconds. In newborn infants, capillary refill can be measured by pressing on the sternum for five seconds with a finger or thumb, and noting the time needed for the colour to return once the pressure is released. The upper normal limit for capillary refill in newborns is 3 seconds. The capillary refill time (CRT) is a common indication of dehydration and decreased peripheral perfusion. It is generally accepted that the test can be highly variable between different patients, and therefore should not be relied upon as a universal diagnostic measure. It is however very useful as supporting evidence for a positive sign of poor perfusion to the extremities. The CRT test (also sometimes referred to as CFT in Podiatric language)is often referred to as the Nail blanch test. A CRT can also be assessed in animals by pressing on their gums as opposed to the sternum which is generally covered with fur or inaccessible.