Ammonia Level Test | Why do we need an ammonia level test?

The Ammonia Level Test helps to measure the level of ammonia in your blood. Ammonia, also known as NH3, is a waste product made by your body during the digestion of protein. Normally, ammonia is processed in the liver, where it is changed into another waste product called urea. Urea is passed through the body in urine.

Ammonia Level Test | Why do we need an ammonia level test?
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If your body can’t process or eliminate ammonia, it builds up in the bloodstream. High ammonia levels in the blood can lead to serious health problems, including brain damage, coma, and even death.

High ammonia levels in the blood are most often caused by liver disease. Other causes include kidney failure and genetic disorders.

Other names: NH3 test, blood ammonia test, serum ammonia, ammonia; plasma

What is this Ammonia Level test used for?

An ammonia level test may be used to diagnose and/or monitor conditions that cause high ammonia levels. These include:

  • Hepatic encephalopathy, a condition that happens when the liver is too diseased or damaged to properly process ammonia. In this disorder, ammonia builds up in the blood and travels to the brain. It can cause confusion, disorientation, and coma. It can sometimes be fatal.
  • Reye syndrome, a serious and sometimes fatal condition that causes damage to the liver and brain. It mostly affects children and teenagers who are recovering from viral infections such as chicken pox or the flu and have taken aspirin to treat their illnesses. The cause of Reye syndrome is unknown. But because of the risk, children and teens should not take aspirin unless specifically recommended by your health care provider.
  • Urea cycle disorders, rare genetic defects that affect the body’s ability to change ammonia into urea.

The test may also be used to monitor the effectiveness of treatment for liver disease or kidney failure.

Why do we need an ammonia level test?

Ammonia (NH3) is produced by cells throughout the body, especially the intestines, liver, and kidneys. Most of the ammonia produced in the body is used by the liver to produce urea. Urea is also a waste product, but it is much less toxic than ammonia. Ammonia is especially toxic to the brain. It can cause confusion, low energy, and sometimes coma.

You may need this test if you have liver disease and are showing symptoms of a brain disorder. Symptoms include:

  • Confusion
  • Excessive sleepiness
  • Disorientation, the condition of being confused about time, place, and/or your surroundings
  • Mood swings
  • Hand tremors

Your child may need this test if he or she has symptoms of Reye syndrome. These include:

  • Vomiting
  • Sleepiness
  • Irritability
  • Seizures

Your newborn baby may need this test if he or she has any of the above symptoms. The same symptoms may be a sign of a urea cycle disorder.

What happens during an ammonia level test?

A health care professional will take a blood sample from a vein in your arm, using a small needle. After the needle is inserted, a small amount of blood will be collected into a test tube or vial. You may feel a little sting when the needle goes in or out. This usually takes less than five minutes.

To test a newborn, a health care provider will clean your baby’s heel with alcohol and poke the heel with a small needle. The provider will collect a few drops of blood and put a bandage on the site.

Will I need to do anything to prepare for the test?

Your health care provider may ask you to stop taking certain drugs that may affect test results. These include:

  • Alcohol
  • Acetazolamide
  • Barbiturates
  • Diuretics
  • Narcotics
  • Valproic acid

You should not smoke for about eight hours before your blood is drawn for the ammonia level test. Also, babies do not need any special preparations before the test.

What do the results of this test mean for a person?

If your results show high ammonia levels in the blood, it may be a sign of one of the following conditions:

  • Liver diseases, such as cirrhosis or hepatitis
  • Hepatic encephalopathy
  • Kidney disease or kidney failure

In children and teens, it may be a sign of Reye syndrome, while in infants, high ammonia levels may be a sign of a genetic disease of the urea cycle or a condition called hemolytic disease of the newborn. This disorder happens when a mother develops antibodies to her baby’s blood cells.

If your results were not normal, your health care provider will need to order more tests to find out the reason for your high ammonia levels. Your treatment plan will depend on your specific diagnosis. If you have questions about your results, talk to your health care provider.

Your tests could come back too high or too low, and you might not have a problem. That’s because sometimes, the way the lab does the test affects the result. It’s best to talk to your doctor about what your results mean.

Normal Ammonia levels range

Average blood ammonia level could indicate that your symptoms are caused by something other than excess ammonia. On the other hand, normal ammonia ranges do not rule out hepatic encephalopathy. Other breakdown products may also affect your mental function and consciousness, and the ammonia level in the brain can be significantly higher than in the blood. This can make it challenging to link symptoms to ammonia blood levels.

Ammonia levels reference range

Adults 10-80 mcg/dL (6-47 µmol/L)
Neonates, 0 to 10 days (enzymatic) 170-341 mcg/dL (100-200 µmol/L)* (PDR).  90-150 mcg/dL
Infants and toddlers from 10 days to 2 years (enzymatic) 68-136 mcg/dL  or (40-8- micromole/L)
Children more than 2 years (enzymatic) 19-60 mcg/dL or (11-35 µmol/L)

High Ammonia level

A significantly high blood ammonia level means that your body is not successfully processing and eliminating ammonia, which could be the source of your symptoms.
An elevated ammonia level in children and adults may indicate that severe liver or kidney damage has hampered the body’s ability to clear ammonia and that the brain may be affected.
High levels in infants may indicate urea cycle impairment due to a rare genetic disorder, such as a deficiency of one of the urea cycle enzymes, or associated with newborn hemolytic disease. Moderate, transient ammonia elevations are pretty standard in newborns, where the level can increase and decrease without causing noticeable signs.
High ranges of glucose and ammonia, in addition to high levels of some liver enzymes, may refer to the asymptomatic child or a teenager is suffering from Reye syndrome. An elevated level may also indicate an undiagnosed urea cycle enzymatic defect.

Low Ammonia Level

Some types of hypertension, such as malignant hypertension (Extremely high blood pressure that occurs suddenly and unexpectedly) and essential (unknown cause high blood pressure), may show low ammonia levels.

Are there any Risks?

Is there anything else I need to know about an ammonia level test?

Some health care providers think blood from an artery may provide more useful information about ammonia than blood from a vein. To get a sample of arterial blood, a provider will insert a syringe into the artery in your wrist, elbow crease, or groin area. This method of Ammonia Level test is not used very often.

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