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Ammonia (serum/plasma concentration)

Published: August 9, 2026Updated: August 16, 2026

This test measures the amount of ammonia, a waste product, in your blood. It helps assess liver function and kidney health.

Quick summary

["Ammonia levels can signal liver or kidney problems that need medical attention."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
98633-1
Short code
SNAP amplitude R ulnar n
Synonyms
SNAP amplitude R ulnar n
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
nerve-conduction
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

Why is this test done?

Your doctor may order this test if you have symptoms like confusion, nausea, or fatigue, or if they suspect liver disease (such as cirrhosis), kidney disease, or metabolic disorders. It can also be part of routine monitoring for people with chronic liver conditions or those on certain medications that affect ammonia levels.

What does a high or low ammonia level mean?

High ammonia levels may indicate liver problems (like liver failure) or kidney issues, as these organs help remove ammonia from your blood. Very low levels are less common but could suggest certain metabolic disorders or overuse of medications that lower ammonia.

How is the test performed?

A blood sample is taken from a vein in your arm. The sample is sent to a lab where it is analyzed to measure ammonia concentration using a specialized method.

What should you do before the test?

Avoid eating a high-protein meal 2–3 hours before the test, as protein digestion increases ammonia levels. Stay hydrated but do not drink excessive fluids right before testing.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Serum/plasma ammonia level

Frequently asked questions

What causes high ammonia levels?
High ammonia can result from liver disease (including cirrhosis), kidney failure, severe dehydration, or certain medications. It may also appear in metabolic disorders like urea cycle defects.
What causes low ammonia levels?
Low ammonia levels are less common but can occur with certain medications (e.g., valproate) or metabolic disorders. Rarely, it may be seen in overproduction of ammonia-destroying enzymes.
How long does it take to get results?
Results are typically available within 1–3 business days, depending on your lab’s processing time. Your doctor will discuss them with you.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

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 16, 2026. · Read our editorial policy