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Ammonia

Published: July 27, 2026Updated: August 25, 2026

Ammonia is a biomarker that measures the amount of ammonia in the blood, which is crucial for assessing liver function and diagnosing hepatic encephalopathy.

Quick summary

Ammonia levels help diagnose liver diseases and hepatic encephalopathy.

Medically reviewed by WellAlly Editorial TeamLast reviewed August 25, 2026Editorial policy

Key facts at a glance

Units
μmol/L
Clinical utility
diagnostic
Result kind
quantitative
FDA-cleared
Roche Ammonia, Abbott Ammonia, Siemens Ammonia
interpretation: {"text":"Ammonia levels within the range of 15–45 μmol/L are considered normal.","label":"Normal"}; {"text":"Levels above 45 μmol/L may indicate liver dysfunction or hepatic encephalopathy.","label":"Elevated"}

Ammonia is a waste product produced primarily in the intestines and is usually converted into urea by the liver for excretion. Elevated ammonia levels can indicate impaired liver function or portal systemic shunting.

The normal reference range for ammonia is typically between 15–45 μmol/L. Levels above this range may suggest liver dysfunction, such as cirrhosis or hepatitis, or conditions like hepatic encephalopathy.

Monitoring ammonia levels is essential in clinical settings to evaluate the severity of liver disease and to guide treatment strategies for patients with hepatic encephalopathy.

Frequently asked questions

What causes elevated ammonia levels?
Elevated ammonia levels can be caused by liver diseases such as cirrhosis, hepatitis, or conditions that affect liver function, including portal systemic shunting.
How is an ammonia test performed?
An ammonia test involves a simple blood draw, usually from a vein in the arm, and the sample is then analyzed in a laboratory.
  1. 1
    Ammonia Blood TestSource
  2. 2
    Liver Function TestsSource

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This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 25, 2026. · Read our editorial policy