Ammonia Levels Test
An ammonia levels test measures the amount of ammonia in your blood. High levels can be toxic to your brain and may indicate liver disease, kidney failure, or a genetic disorder.
What this test measures
This test measures the amount of ammonia (NH3) in a sample of your blood. Ammonia is a waste product made by bacteria in your intestines when you digest protein.
What your results mean
Reference ranges vary by laboratory and by your age and sex. MedlinePlus does not publish a single normal range for this test — always read your result against the range printed on your own lab report and discuss it with your provider.
Higher-than-normal results
High ammonia levels usually mean your body is having trouble getting rid of ammonia. Possible causes include liver diseases (such as cirrhosis or hepatitis), hepatic encephalopathy, kidney disease or failure, certain genetic disorders (including urea cycle disorders), Reye syndrome, or taking certain medicines.
Lower-than-normal results
Low levels are generally normal and healthy.
Frequently asked questions
What is an ammonia levels test?
It measures the amount of ammonia in your blood. Ammonia is a waste product that can be toxic to your brain if levels get too high.
Why would I need this test?
To help diagnose conditions that cause high ammonia levels, such as liver disease, hepatic encephalopathy, Reye syndrome, or urea cycle disorders.
What does a high ammonia level mean?
It usually means your body is having trouble getting rid of ammonia. This can be due to liver disease, kidney failure, certain genetic disorders, or Reye syndrome.
What does a low ammonia level mean?
Low levels are generally normal and healthy.
Can this test diagnose a condition by itself?
No, the test alone cannot diagnose a condition. It is used with other tests and your symptoms to help find the cause.
Related lab tests
Sources
- MedlinePlus: Ammonia Levels — NIH MedlinePlus
Last updated . Information is aggregated from official public sources and is not a substitute for professional medical care.