Plasma Ammonia or NH3.
Normal ranges are about (depending on lab) Adults: 10 to 80 mcg/dL
Your liver may not work properly if you have high levels of ammonia in your blood. Ammonia is a chemical made by bacteria in your intestines while you process protein. Your body treats ammonia as a waste product. It turns it into glutamine and urea. Then the urea travels to the kidneys and is eliminated in your urine.
Ammonia will build up if the liver is too damaged to get rid of urea. This can sometimes happen if you have advanced liver disease. Too much ammonia in your body can cause psychological problems like confusion, tiredness, and possibly coma or death. In a cirrhotic patient it can cause the complications of hepatic encephalopathy (HE).