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Ammoniatissscnt

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

This test measures the amount of ammonia in your blood to help evaluate liver function and diagnose certain metabolic disorders.

Quick summary

{"Measures ammonia levels in blood serum","Helps diagnose and monitor liver disease and hepatic encephalopathy","Used to evaluate conditions like Reye syndrome","Requires fasting and special sample collection procedures","Results help doctors assess how well your liver processes waste products"}

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

Key facts at a glance

LOINC
16363-4
Short code
Ammonia Tiss-sCnt
Synonyms
Ammonia Tiss-sCnt
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Critical range
— – 200 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
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?

The Ammonia Blood Test measures the level of ammonia (NH3) in your blood. Ammonia is a waste product that is normally processed by your liver and converted to urea, which is then excreted by your kidneys. When the liver is not functioning properly, ammonia can build up in the blood and cause serious health problems.

Why do I need this test?

Your doctor may order an ammonia test if you have symptoms of liver disease such as confusion, drowsiness, tremors, or unusual body odor. It is also used to monitor patients with known liver disease, evaluate the severity of hepatic encephalopathy (a condition where liver dysfunction affects brain function), and diagnose certain metabolic disorders or Reye syndrome.

How is the test performed?

A healthcare professional will draw a blood sample from a vein in your arm. The blood is collected in a special tube that contains an anticoagulant to prevent clotting. It is important that the sample be placed on ice immediately and processed quickly, as ammonia levels can change after the blood is drawn. You may need to fast for 8-12 hours before the test, and your doctor may ask you to avoid certain medications and smoking, as these can affect ammonia levels.

Are there any risks?

The risks of having blood drawn are minimal and may include slight pain, bruising, or bleeding at the puncture site. Some people may feel dizzy or faint during the blood draw. These risks are generally temporary and resolve quickly.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Frequently asked questions

What do high ammonia levels mean?
High ammonia levels usually indicate that your liver is not properly processing waste products. This can be caused by liver diseases such as hepatitis, cirrhosis, or liver failure. It may also occur in conditions like hepatic encephalopathy, Reye syndrome, or certain inherited metabolic disorders. Your doctor will interpret your results in the context of your overall health and other test results.
Do I need to prepare for the test?
Yes, you may need to fast for 8-12 hours before the test. You should also avoid smoking, as nicotine can increase ammonia levels. Tell your doctor about all medications you are taking, as some drugs can affect ammonia levels. Follow any specific instructions given by your healthcare provider.
How long does it take to get results?
Results are typically available within a few hours to a day, depending on the laboratory. Since ammonia levels can change rapidly after blood collection, samples are usually processed immediately. Your doctor will discuss your results with you at your follow-up appointment.
What happens if my ammonia levels are high?
If your ammonia levels are elevated, your doctor will determine the underlying cause and recommend appropriate treatment. Treatment may include dietary changes (such as restricting protein intake), medications to help remove ammonia from your blood, lactulose to help eliminate ammonia through the bowels, or treatment for the underlying liver condition. In severe cases, hospitalization may be necessary.
  1. 1
    MedlinePlus - Ammonia Blood TestSource
  2. 2
    May Clinic - Ammonia Level TestSource
  3. 3
    LOINC - Ammonia [Moles/volume] in Serum or PlasmaSource

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