Ammonia is a by-product of protein catabolism; most of it is created by bacteria acting on proteins present in the gut. Ammonia is metabolized by the liver and excreted by the kidneys as urea. Elevated levels resulting from hepatic dysfunction may lead to encephalopathy. Venous ammonia levels are not a reliable indicator of hepatic coma.

Normal Lab Value for Ammonia

  • Adults: 35 – 65 mcg/dL

Nursing Considerations

  • Instruct the client to fast, except for water, and to refrain from smoking for 8 to 10 hours before the test; smoking increases ammonia levels.
  • Place the specimen on ice and transport to the laboratory immediately.