gums under the thumb have been blanched out, the thumb can be
removed. The blanched out area should return to normal color in less
than 1-2 seconds.
Note: If the cat is
dehydrated, the membranes will be dry and the capillary refill time
will be prolonged (>2-3 seconds).
A cat in shock will also have an increased capillary refill time.
A video of this procedure can be found below.