Medical expert of the article

Hematologist, oncohematologist

New publications

Ammonia in serum

Alexey Kryvenko, medical expert
Last reviewed: 04.07.2025

All iLive content is medically reviewed or fact checked to ensure as much factual accuracy as possible.

We have strict sourcing guidelines and only link to reputable media sites, academic research institutions and, whenever possible, medically peer reviewed studies. Note that the numbers in parentheses ([1], [2], etc.) are clickable links to these studies.

If you feel that any of our content is inaccurate, out-of-date, or otherwise questionable, please select it and press Ctrl + Enter.

Ammonia is a product of protein metabolism, formed in all tissues. The largest amount of ammonia (80%) is formed inside the intestine under the influence of bacteria. Nitrogen compounds such as amino acids, uric acid, urea in the presence of bacterial enzymes (protease, urease, amine oxidase) are metabolized to ammonia. Ammonia is also formed in the cells of the intestinal mucosa from glutamine. Metabolism of ammonia to urea occurs in the liver during the ornithine cycle. This process can be disrupted both as a result of hyperproduction of ammonia in the intestine, and due to a decrease in its conversion to urea in liver pathology.

Reference values for serum ammonia (ammonia nitrogen) concentration

Age	Serum ammonia concentration
Age	Mcg/dl	µmol/l
Newborns	90-150	64-107
0-2 weeks	79-129	56-92
Older than 1 month	29-70	21-50
Adults	15-45	11-32

trusted-source [ 1 ], [ 2 ], [ 3 ], [ 4 ], [ 5 ], [ 6 ], [ 7 ]