Ammonia, Plasma

There are no preparation instructions.

The following is a list of what is included in the item above. Click the test(s) below to view what biomarkers are measured along with an explanation of what the biomarker is measuring.

Also known as: Ammonia Plasma

Ammonia (P)

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The Ammonia, Plasma test contains 1 test with 1 biomarker.

IMPORTANT - The specimen for this test must be collected at a patient service center that can collect, store and transport frozen samples as outlined below.  

IMPORTANT: Before ordering this lab test, check and confirm with the selected patient service center to ensure that they can collect, store and transport frozen samples as outlined below.

Preferred Specimen(s) 

2 mL frozen plasma collected in an EDTA (lavender-top) tube

Collection Instructions 

Collect blood from stasis-free vein of patient (e.g., no tourniquet). Patient should not clench fist during collection, as muscular exertion often increases venous ammonia levels. Patient should avoid smoking prior to phlebotomy since smoking increases plasma ammonia levels. Tubes should be filled completely and kept tightly stoppered at all times. Place immediately on ice. Separate plasma from cells within 20 minutes and freeze plasma immediately.

Transport Temperature 


Specimen Stability 

Room temperature: Unstable
Refrigerated: Unstable
Frozen -20° C: 72 hours
Frozen -70° C: 7 days

Reject Criteria 

Hemolysis • Lipemia • Received thawed • PPT Potassium EDTA (white-top) tube

Brief Description: The Ammonia Plasma test is a medical laboratory examination that measures the concentration of ammonia in the plasma, which is the liquid part of the blood. Ammonia is a waste product produced during the breakdown of proteins and is normally processed and eliminated by the liver. This test is crucial in assessing liver function and identifying conditions that may lead to ammonia accumulation in the bloodstream.

Also Known As: NH3 Test, NH3 Plasma Test, Ammonia Blood Test

Collection Method: Blood Draw

Specimen Type: Plasma

Test Preparation: No preparation required

When is an Ammonia test ordered?

An ammonia test may be required if an infant exhibits any of these symptoms within the first few days after delivery:

  • Irritability
  • Vomiting
  • Lethargy
  • Seizures

A medical professional may order an ammonia test if a child exhibits these symptoms a week after a viral infection like the flu or chicken pox or if they think the child might have Reye syndrome.

An ammonia level may be requested to help determine the source of the change in consciousness when individuals exhibit mental changes, disorientation, tiredness, or slide into a coma and may have liver disease or renal failure. When a person suddenly becomes more acutely ill, an ammonia level as well as other liver function tests may be requested in patients with stable liver disease.

What does an Ammonia blood test check for?

A byproduct of the breakdown of protein in the intestines, ammonia is largely produced by bacteria. Excess ammonia can build up in the blood if it is not properly digested and eliminated from the body. This examination calculates the blood's ammonia level.

Normally, ammonia travels through the blood to the liver, where it is transformed into the compounds urea and glutamine. Once at the kidneys, the urea is removed through the urine. Ammonia builds up in the blood and can enter the brain if this "urea cycle" does not completely break down the ammonia.

The brain is poisonous to ammonia. For instance, ammonia and other substances processed by the liver can build up in the brain and induce a condition known as hepatic encephalopathy when liver function is considerably impaired as a result of diseases like cirrhosis or hepatitis.

Mental and neurological abnormalities brought on by hepatic encephalopathy can result in confusion, disorientation, tiredness, eventually a coma, and even death.

Children and infants with elevated ammonia levels may vomit often, get agitated, and become progressively more sluggish. If untreated, they could develop respiratory problems, suffer seizures, or fall into a coma.

Lab tests often ordered with an Ammonia test:

When an Ammonia test is ordered, it's often part of a broader evaluation of liver function and potential liver-related issues. Here are some tests commonly ordered alongside it:

  1. Liver Function Test:

    • Purpose: To assess liver health by measuring enzymes, proteins, and substances produced or processed by the liver, including alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), bilirubin, and albumin.
    • Why Is It Ordered: To evaluate overall liver function and to help diagnose liver diseases or damage.
  2. Complete Blood Count (CBC):

    • Purpose: To evaluate overall blood health, including red and white blood cells and platelets.
    • Why Is It Ordered: To check for signs of anemia, infection, or other blood-related issues that can occur with liver disease.
  3. Prothrombin Time (PT) and International Normalized Ratio (INR):

    • Purpose: To measure how long it takes blood to clot.
    • Why Is It Ordered: To assess liver function, as the liver produces clotting factors, and prolonged clotting time can indicate liver dysfunction.
  4. Electrolyte Panel:

    • Purpose: To measure key electrolytes in the blood.
    • Why Is It Ordered: To evaluate electrolyte balance, which can be affected by liver disease and conditions causing altered ammonia levels.
  5. Blood Urea Nitrogen (BUN) and Creatinine:

    • Purpose: To assess kidney function.
    • Why Is It Ordered: To rule out renal causes of elevated ammonia levels and to assess overall renal function, as kidney disease can coexist with liver disease.
  6. Lactate Level:

    • Purpose: To measure the level of lactate in the blood.
    • Why Is It Ordered: To evaluate for lactic acidosis, which can occur in severe liver dysfunction and other critical conditions.

These tests, when ordered alongside an Ammonia test, provide a comprehensive evaluation of liver function and potential liver-related disorders. They are crucial for diagnosing the cause of elevated ammonia levels, assessing the severity of liver dysfunction, and guiding appropriate treatment. The specific combination of tests will depend on the individual’s symptoms, clinical presentation, and medical history.

Conditions where an Ammonia test is recommended:

  1. Liver Disease: Conditions like cirrhosis, hepatitis, and other liver disorders can impair the liver's ability to process ammonia, leading to its accumulation in the bloodstream.
  2. Congenital Metabolic Disorders: Inherited disorders such as urea cycle disorders can lead to a buildup of ammonia in the blood due to a deficiency in the enzymes responsible for ammonia conversion.
  3. Reye's Syndrome: A rare but serious condition often affecting children recovering from viral infections, leading to liver and brain dysfunction and elevated ammonia levels.

How does my health care provider use an Ammonia test?

The ammonia test is used to identify blood levels of ammonia that are elevated and may be brought on by conditions such severe liver illness, kidney failure, Reye syndrome, or a rare hereditary defect of the urea cycle. The test may be employed to aid in determining what is causing a person's changes in behavior and consciousness.

Ammonia is a waste product that the body naturally produces. It primarily results from bacteria in the intestines digesting protein. Excess ammonia can build up in the blood and travel into the brain, where it is poisonous, if the liver is not properly cleansed from the body and processing it.

In order to determine the etiology of a coma or to support the diagnosis of Reye syndrome or hepatic encephalopathy brought on by different liver illnesses, an ammonia test may be requested along with additional tests like glucose, electrolytes, kidney, and liver function tests. A uncommon urea cycle malfunction may also be diagnosed and the severity of the condition assessed using an ammonia level.

There is still debate over the clinical usefulness of the ammonia test for hepatic encephalopathy treatment monitoring among healthcare professionals. Blood ammonia levels do not accurately predict the severity of hepatic encephalopathy since the illness can be brought on by the accumulation of several poisons in the blood and brain.

What do my Ammonia test results mean?

The signs and symptoms of the individual may be brought on by an ammonia level in the blood that is much higher than normal. This signals that the body is not adequately removing and digesting ammonia from the body.

An abnormally high level in newborns can also be a sign of newborn hemolytic illness in addition to a hereditary urea cycle enzyme deficit or abnormality. Newborns frequently experience moderate, brief elevations in ammonia levels, which can rise and fall without manifesting any symptoms.

When children and teens with symptoms have elevated ammonia levels and low glucose levels, Reye syndrome may be present. A higher quantity can also be a sign of an unidentified urea cycle enzymatic malfunction.

An increased ammonia level in both children and adults may signal significant liver or renal impairment that has compromised the body's capacity to eliminate ammonia and that the brain may be harmed. Acute or persistent illnesses frequently act as triggers, raising ammonia levels to the point that a patient has trouble excreting the ammonia.

If a person's blood ammonia level is normal, it's possible that something other than too much ammonia is to blame for their signs and symptoms. Normal ammonia levels do not, however, rule out hepatic encephalopathy. Ammonia levels in the brain may be significantly greater than those in the blood, and other wastes may also play a role in modifications to mental processes and consciousness. This can make it challenging to relate a person's symptoms to ammonia blood levels.

With some types of hypertension, such as essential and malignant, the quantity of ammonia may be reduced.

Most Common Questions About the Ammonia Plasma test:

Test Purpose and Indications

Why is the Ammonia Plasma test ordered?

The Ammonia Plasma test is primarily ordered to help diagnose the cause of changes in behavior or consciousness. Elevated ammonia levels may be seen with conditions that affect the liver's function and its ability to clear toxins from the blood, such as cirrhosis or liver disease.

How can the Ammonia Plasma test assist in diagnosing hepatic encephalopathy?

Hepatic encephalopathy is a complication of liver disease and is characterized by confusion, altered levels of consciousness, and potential coma. Elevated ammonia levels in the blood can be a hallmark of this condition. The Ammonia Plasma test helps confirm a diagnosis in patients exhibiting these symptoms, especially if they have a known liver condition.

Test Interpretation

What does a high level of ammonia in the plasma indicate?

An elevated ammonia level in the plasma suggests the liver isn't effectively breaking down and removing ammonia from the blood. This could be due to liver dysfunction or damage. Conditions such as cirrhosis, acute liver failure, or Reye syndrome can lead to increased ammonia levels.

If the Ammonia Plasma test shows normal levels, does it rule out liver diseases?

While normal ammonia levels can suggest the liver is functioning correctly in terms of ammonia metabolism, it doesn't rule out all liver diseases. The liver has multiple functions and can have reduced functionality in one area while still maintaining others. Other tests and clinical evaluations are necessary to get a comprehensive understanding of liver health.

General Information

How is the sample for the Ammonia Plasma test typically collected?

The sample for the Ammonia Plasma test is usually drawn from a vein in the arm. It's important that the sample is processed quickly and under specific conditions to prevent the blood cells from continuing to produce ammonia, which can give falsely elevated results.

Does diet or medication affect the results of the Ammonia Plasma test?

Certain medications can increase ammonia levels, such as valproic acid and some diuretics. Additionally, a high-protein diet can raise blood ammonia levels, while a low-protein diet can lower them. It's essential to share all medications and dietary habits with the healthcare provider before the test.

We advise having your results reviewed by a licensed medical healthcare professional for proper interpretation of your results.

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