Ammonia is one of the normal byproducts of the breakdown of proteins in the body.
Ammonia is normally removed from the body by the liver. Therefore, the plasma ammonia test is used to screen for severe liver damage. The test can also be used to help predict liver failure and a patient s risk of coma. High blood ammonia levels can affect brain function, causing excessive sleepiness, cloudy thinking and a characteristic tremor of the hands called a flapping tremor. A plasma ammonia test may be ordered by a physician if a patient is experiencing any of these symptoms.