Also Known as: NH3 test, blood ammonia test, serum ammonia
What is an ammonia test?
This test determines the amount of ammonia is present in your blood. Ammonia, also known as NH3, is a waste product produced by the body due to protein breakdown. Ammonia is usually processed in the liver, where it is converted to urea (a waste product) which is expelled through the body in urine. Ammonia builds up in the blood if your body can't process or eliminate it. High blood ammonia levels can cause significant health issues such as brain damage, unconsciousness, and death.
What is the test used for?
This test can be used to diagnose conditions that result in high ammonia levels in the blood. These are some of them:
Hepatic encephalopathy: A condition that occurs when the liver becomes too damaged to process ammonia effectively. Toxins build up in the blood and flow to the brain in this condition. It can produce unconsciousness, confusion, and disorientation and can be fatal in some cases. Certain healthcare practitioners use the ammonia test to monitor the effectiveness of hepatic encephalopathy treatment, but there is no broad consensus on this practice. Blood ammonia levels do not correspond well with the severity of hepatic encephalopathy, which can be caused by the accumulation of various other toxins in the blood and brain.
Reye’s syndrome: It is a serious and fatal disease affecting the liver and the brain. Reye syndrome has no known etiology. It primarily affects children and teenagers who have taken aspirin to treat viral diseases such as flu or chickenpox. However, children and teenagers should only take aspirin if their doctor recommends explicitly it due to the underlying risk.
Disorders of the urea cycle: These are uncommon genetic defects that disrupt the body's capacity to convert ammonia to urea.
The test can also be used to monitor the treatment of kidney failure and liver disease.
Why and when do you need this test?
If you have liver disease or are experiencing symptoms of a brain disorder, you may need this test. Among the signs and symptoms are:
- Excessive sleeping
- Disorientation (a mental state in which you are unsure of your time, place, or surroundings)
- Mood Swings
- Tremors in hands
The symptoms listed above can occur in the presence or absence of liver disease or renal failure. An ammonia level and other liver function tests may be requested when you become acutely ill and have stable liver disease.
If your child exhibits symptoms of Reye syndrome or urea cycle disorder, they may need this test. These are some of them:
What kind of sample is required for the test?
A healthcare provider will use a small needle to obtain a blood sample from a vein in your arm. A small amount of blood will be collected into a test tube or vial once the needle is inserted. When the needle goes in or out, it may sting a little. It usually takes less than five minutes to complete this process.
Do you need to prepare for the test?
Before an ammonia test, you should not exercise or smoke for at least eight hours. No specific preparations are required for babies.
Are there any risks to this test?
Having a blood test carries relatively little risk. You or your child may experience minor pain or bruising where the needle was inserted, but most symptoms disappear quickly.
What do the test results mean?
If your blood tests indicate high levels of ammonia, it could mean one of the following conditions:
- Liver diseases such as hepatitis or cirrhosis
- Hepatic encephalopathy
- Kidney disease
- A sign of Reye's syndrome (in children and teenagers)
High ammonia levels in babies could indicate
- A genetic urea cycle disorder
- Hemolytic disease of the newborn.
Ammonia levels may also be elevated as a result of:
- Gastrointestinal bleeding
- Recent Muscular activity
- Use of a tourniquet
- High protein intake
- Premature babies with respiratory distress
- Use of Alcohol, barbiturates, diuretics, high-dose chemotherapy, valproic acid, and opioids
Some antibiotics, such as neomycin and metronidazole, have been shown to lower ammonia levels. If your results were abnormal, your doctor would need to perform additional tests to determine the cause of your elevated ammonia levels. Your diagnosis will determine your treatment plan.