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Ammoniabldmcnc

Published: August 9, 2026Updated: August 17, 2026

A blood ammonia test measures the level of ammonia in your blood to evaluate how well your liver is working and to help diagnose certain metabolic disorders.

Quick summary

{"Measures ammonia levels in your blood","Helps assess liver function and detect liver disease","Used to diagnose conditions like hepatic encephalopathy","Simple blood draw test, usually done in the morning","Results help doctors determine treatment for liver or metabolic conditions"}

Medically reviewed by WellAlly Editorial TeamLast reviewed August 17, 2026Editorial policy

Key facts at a glance

LOINC
32664-5
Short code
Ammonia Bld-mCnc
Synonyms
Ammonia Bld-mCnc
Category
chemistry
Sample
whole-blood
Container
Lavender-top (EDTA)
Units
N/A
Critical range
— – 200 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
3 mL
Stability
Room temperature: 4h, Refrigerated: 24h
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
4–24 hours
Order
routine

What is this test?

A blood ammonia test is a laboratory test that measures the amount of ammonia (a waste product) in your blood. Normally, your liver converts ammonia into urea, which is then excreted in urine. When the liver is not functioning properly, ammonia can build up in the blood, which may cause various symptoms and complications.

How is the test performed?

A healthcare professional will draw a small sample of blood from a vein in your arm using a needle. The sample is then placed in a special tube and sent to a laboratory for analysis. The test is typically performed in the morning after fasting overnight, as food intake can affect ammonia levels.

How to prepare for the test?

Before the test, your doctor may ask you to fast for 8-12 hours. You should avoid smoking and strenuous exercise before the test, as these can affect ammonia levels. Inform your doctor about all medications you are taking, as some drugs can influence test results. Your doctor may ask you to temporarily stop certain medications before the test.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings2

Frequently asked questions

Why do I need a blood ammonia test?
Your doctor may order this test if you have symptoms of liver disease such as yellowing of the skin or eyes (jaundice), abdominal swelling, or unexplained confusion. It is also used to monitor patients with known liver disease and to evaluate the effectiveness of treatment.
What do abnormal results mean?
High ammonia levels usually indicate that your liver is not properly removing ammonia from your blood. This can be due to liver disease, certain metabolic disorders, or other conditions. Your doctor will interpret your results in context with your overall health and other test results.
Is the test painful?
You may feel a brief sting or pinch when the needle is inserted to draw blood. This is generally well-tolerated. The risks are minimal and include slight bruising or bleeding at the injection site.
How long does it take to get results?
Results are typically available within a few hours to one day. Your healthcare provider will contact you with the results and explain what they mean for your health.
Are there any foods or medications I should avoid before the test?
Your doctor may ask you to fast before the test. Avoid alcohol and certain medications as instructed by your doctor. Smoking and vigorous exercise should also be avoided before the test as they can affect ammonia levels.
  1. 1
    MedlinePlus - Ammonia Blood TestSource
  2. 2
    Mayo Clinic - Blood Ammonia TestSource
  3. 3
    ARUP Consult - AmmoniaSource

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.

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 17, 2026. · Read our editorial policy