Quick Facts
- Sample: Blood (vein)
- Fasting: Not required
- Turn-around: 1-2 business days. May take longer based on weather, holiday, or lab delays.
Benefits
- Detects dangerous ammonia buildup that damages brain function and requires urgent care
- Screens for liver disease, metabolic disorders, and hepatic encephalopathy with over 90% diagnostic accuracy (Mayo Clinic 2024)
- Supports early intervention for conditions affecting mental clarity and neurological health
- Guides treatment monitoring in patients with known liver or metabolic conditions
- Identifies rare genetic disorders like urea cycle disorders in newborns and symptomatic individuals (MedlinePlus 2022)
Who Is This Test For?
- Individuals experiencing confusion, lethargy, or unexplained changes in mental status
- People with diagnosed liver disease or cirrhosis needing ongoing monitoring
- Newborns suspected of metabolic or urea cycle disorders
- Patients with mood swings, muscle control problems, or declining cognitive function
- Anyone concerned about ammonia-related neurological damage from existing health conditions
How It Works – Just 3 Steps
- Order online and visit a lab location near you—2,000+ locations nationwide
- Blood sample collected from your vein using specialized cold heparinized tubes
- Receive results typically within 24 hours to secure online account
FAQ
What is the purpose of this test? This test measures ammonia levels in your blood to detect hyperammonemia and diagnose conditions impairing liver or kidney function, metabolic disorders, or urea cycle problems (Mayo Clinic 2024).
Who would benefit from this test? Anyone with altered mental status, diagnosed liver disease, suspected metabolic disorders, or symptoms like confusion and lethargy should consider this test (UCSF Health 2023).
When should I order an Ammonia Plasma Test? Order this test if you experience confusion, uncontrolled movements, lethargy, or mood swings, or if you need to monitor a known liver or metabolic condition (MedlinePlus 2022).
How do I interpret the results? Your healthcare provider will compare your results to normal ranges and assess your symptoms and medical history. See the interpretation table below for general guidance.
Are there special preparation steps? Avoid smoking and medications like diuretics and narcotics before testing. Inform your provider of all substances you take (UCSF Health 2023).
What makes this test urgent in some cases? Elevated ammonia can damage your brain within hours and cause coma or permanent neurological damage if untreated, making prompt diagnosis and treatment critical (Cleveland Clinic 2025).
More Details
What is the purpose of this test?
The Ammonia Plasma Test measures the concentration of ammonia in your blood to detect hyperammonemia—abnormally high ammonia levels. Your body produces ammonia as a byproduct of digestion and metabolism. Normally, your liver converts ammonia into urea, which your kidneys safely excrete. When this process fails, ammonia accumulates and can damage your brain (Mayo Clinic 2024). This test provides crucial diagnostic information for liver dysfunction, kidney failure, and metabolic disorders.
Who would benefit from this test?
This test is ideal for patients with altered mental status, diagnosed liver disease, newborns suspected of metabolic disorders, and individuals with symptoms suggesting hepatic encephalopathy (UCSF Health 2023). Health-conscious individuals using direct-to-consumer labs can order this test for early detection and monitoring of conditions affecting liver and brain health. It's particularly valuable if you have a family history of urea cycle disorders or experience unexplained neurological changes.
When should I order this test?
Order this test when you experience symptoms such as confusion, lethargy, uncontrolled movements, coma, or unexplained neurological changes (MedlinePlus 2022). If you have been diagnosed with liver disease, cirrhosis, or metabolic conditions, regular monitoring supports ongoing care. Newborns with suspected urea cycle disorders or inborn errors of metabolism may be screened through this test as part of metabolic workup protocols.
How do I interpret the results?
Plasma Ammonia Level: <50 micromoles/L
- What It Means: Normal
- Typical Action: Continue routine health monitoring
Plasma Ammonia Level: 50–100 micromoles/L
- What It Means: Mildly elevated
- Typical Action: Consult healthcare provider; repeat testing may be recommended
Plasma Ammonia Level: >100 micromoles/L
- What It Means: Significantly elevated
- Typical Action: Seek urgent medical evaluation; may indicate hepatic encephalopathy or metabolic disorder
Elevated ammonia correlates with increased hospitalization and healthcare costs in liver disease patients, making early detection and treatment critical (Cleveland Clinic 2025).
Disclaimer: Reference ranges may vary by laboratory. Listed ranges are general guidelines and may differ from those used by the performing lab. Always consult your healthcare provider for interpretation.
Pre-test preparation
Avoid smoking, alcohol, diuretics, barbiturates, and narcotics before your test, as these substances can affect ammonia levels. Blood samples must be collected in cold heparinized tubes and transported on ice to prevent false elevations (UCSF Health 2023). Inform your provider of all medications and supplements you're taking. Fasting is generally not required for this test.
How often should I get tested?
- Monitoring known liver disease: Every 3–6 months or as recommended
- Hepatic encephalopathy management: Baseline, then per clinical protocol
- Following diagnosis of metabolic disorder: Per healthcare provider's guidance
- Routine health screening: As-needed based on symptoms or risk factors
- Post-treatment evaluation: Follow-up within 1–2 weeks, then as advised
Why early detection matters
Hyperammonemia affects up to 60% of patients with advanced liver disease and is a major cause of hepatic encephalopathy (JAMA 2023). Early ammonia testing with sensitive assays improves diagnostic accuracy for metabolic and hepatic encephalopathy by over 90% (Mayo Clinic 2024). Prompt identification and treatment of hyperammonemia reduce neurological damage and improve survival rates. Urea cycle disorders, detected via ammonia testing, occur in about 1 in 35,000 live births and carry significant morbidity if untreated (MedlinePlus 2022).
Related tests you may consider
Liver Function Panel — Assesses liver enzyme activity, providing context for ammonia elevation and overall hepatic health
Blood Urea Nitrogen (BUN) Test — Complements ammonia testing to evaluate nitrogen waste clearance and kidney function
Amino Acid Analysis Plasma Profile - Genova Test Kit — Measures amino acids in plasma to help detect urea cycle imbalances and inherited metabolic disorders that may cause elevated ammonia levels.
