HomeLab TestsAmmonia Levels
Back to Lab Tests
Ammonia Levels
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Lab Tests

Ammonia Levels

The ammonia levels test measures the amount of ammonia in the blood to help diagnose conditions that prevent the body from properly processing this toxic waste product.

Overview

Ammonia (NH3) is a waste product created by intestinal bacteria during protein digestion. In a healthy body, the liver converts ammonia into urea, which is then excreted by the kidneys. This process is known as the urea cycle. Because ammonia is toxic to the brain, high levels—a condition called hyperammonemia—can lead to severe complications, including permanent brain damage, coma, or death.

Why the Test is Performed

Testing is used to diagnose or monitor conditions that cause ammonia buildup, including:

  • Hepatic encephalopathy: A condition where the liver cannot break down toxins, leading to brain dysfunction.
  • Reye syndrome: A rare, life-threatening disease affecting the brain and liver, often linked to aspirin use during viral infections in children.
  • Urea cycle disorders (UCDs): Genetic conditions where the body lacks the enzymes necessary to convert ammonia into urea.

Symptoms of High Ammonia

Symptoms vary by age and severity but may include:

  • General: Irritability, confusion, headache, vomiting, mood swings, and seizures.
  • Neurological: Lack of mental alertness, extreme sleepiness, and loss of muscle coordination.
  • In children/infants: Developmental delays, failure to thrive, lack of muscle tone, and respiratory distress (grunting or fast breathing in newborns).

Procedure and Preparation

Blood is typically drawn from a vein in the arm. In some cases, a provider may draw blood from an artery for higher accuracy, which may require numbing medication. For newborns, a heel stick is used.

Preparation may include fasting and avoiding smoking, alcohol, and strenuous exercise. You may be asked to pause certain medications, such as diuretics or opioid pain relievers, but you should never stop prescribed medication without consulting your provider.

Interpreting Results

Normal ammonia levels are low. If results are higher than normal, it indicates the body is struggling to eliminate ammonia. This may be caused by liver disease (such as cirrhosis or hepatitis), kidney failure, genetic disorders, or specific medications. High results usually necessitate further testing to identify the underlying cause and determine an appropriate treatment plan.

Frequently Asked Questions

cute decompensation of cirrhosis (e.g., infection, gastrointestinal bleeding, constipation, high‑protein meals, or use of sedatives like benzodiazepines) can overwhelm the liver’s capacity to convert ammonia to urea, leading to hyperammonemia and hepatic encephalopathy.
Initial management focuses on reducing ammonia production and enhancing its removal: lactulose (to trap ammonia in the gut), rifaximin (antibiotic to decrease ammonia‑producing bacteria), protein‑adjusted diet, and correction of precipitating factors (e.g., treat infection, stop sedatives). In severe cases, intravenous sodium benzoate, L‑ornithine‑L‑aspartate, or hemodialysis may be required.
Most labs ask you to fast for 8‑12 hours, avoid strenuous exercise, and refrain from alcohol, smoking, and certain medications (e.g., diuretics, lactulose, or antibiotics) for 24 hours unless your doctor says otherwise. The sample should be kept on ice and processed quickly; inform the phlebotomist that the test is for ammonia so proper handling is used.
Yes. Certain supplements containing high amounts of amino acids (e.g., protein powders, branched‑chain amino acid formulas) can increase ammonia production. Medications such as valproic acid, certain chemotherapy agents, and some antiepileptics may also elevate ammonia. Always list all supplements and drugs to your clinician before testing.
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.

kontakt@hittavard.se

Ⓒ 2024. Alla rättigheter förbehålls av juxt ab

Sök
Om ossVillkor och policyVanliga frågorKontakta oss