[2][4] These values should be considered as decision limits and the normal reference ranges of individual laboratories should be used for clinical interpretation.

[4] When ammonia levels rise greater than 200 μmol/L, serious symptoms, including seizures, encephalopathy, coma, and even death, can occur.

[2] Hyperammonemia is one of the metabolic derangements that contribute to hepatic encephalopathy, which can cause swelling of astrocytes and stimulation of NMDA receptors in the brain.

Dietary protein, a metabolic source of ammonium, is restricted, and caloric intake is provided by glucose and fat.

Similarly, sodium benzoate reduces ammonia content in the blood by conjugating with glycine to form hippuric acid, which is rapidly excreted by the kidneys.

[15] Treatment of severe hyperammonemia (serum ammonia levels greater than 1000 μmol/L) should begin with hemodialysis if it is otherwise medically appropriate and tolerated.