Extended Liver Function Test with Ammonia and AST — Qualitative
A legacy qualitative liver test that includes AST and ammonia. It helps evaluate liver injury and how the body handles ammonia.
["This test looks for signs of liver dysfunction and impaired ammonia processing."]
Key facts at a glance
- LOINC
- 15808-9
- Short code
- Deprecated Ltx Glv Ext Ammon IgE RAST Ql
- Synonyms
- Deprecated Ltx Glv Ext Ammon IgE RAST Ql
- Category
- liver
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 10
- Ref high
- 40
- Critical range
- — – 500 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- CPT
- 84484
- SNOMED
- 302774002
- Specimen volume
- 5 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–24 hours
- Order
- routine
What is this test?
This is a legacy, extended liver-function test that includes aspartate aminotransferase (AST) and ammonia. Some laboratories may include additional liver-related measurements, and this version reports a qualitative result.
Why might I need this test?
It may be ordered to evaluate suspected liver disease, monitor liver problems, or investigate confusion, unusual fatigue, or other symptoms that could be related to the liver or the buildup of ammonia.
How is the test performed?
A laboratory specimen, usually blood, is analyzed for AST, ammonia, and any other components included by the testing laboratory. Blood used for ammonia testing may need special handling and prompt processing.
How do I prepare for the test?
Follow the laboratory's instructions and tell the healthcare provider about medicines, supplements, alcohol use, and recent illness. Avoid eating or drinking only if you are specifically told to fast, and do not stop prescribed medicines unless instructed.
Reference range
Adult: 10-40 U/LN/A
No special preparation required. Avoid fatty meals before the test if possible.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
An abnormal AST result may occur with liver-cell injury, alcohol-related liver disease, medication effects, muscle injury, or other conditions. An abnormal ammonia result can reflect impaired liver function, reduced blood flow to the liver, certain medicines, or problems involving the kidneys. The overall pattern must be interpreted by a healthcare professional because individual results do not establish a diagnosis.
Short name
Extended liver function test
Frequently asked questions
What does AST measure?
Why is ammonia included?
Why was this test labeled deprecated?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
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 17, 2026. · Read our editorial policy