- Liver evaluation using a FibroScan, a medical device that uses elastic waves to measure liver stiffness in a process similar to ultrasound scanning. For this test, the subjects lies flat on the back with the arm extended out. The tip of the machine s probe is covered with gel and placed on the skin between the ribs at the level of the right lobe of the liver. The machine produces a little tap on the skin that sends a wave out and checks how fast the wave moves. The speed of the wave indicates the amount of scarring in the liver.