Ammonia Levels
An ammonia levels test measures the amount of ammonia in a sample of your blood.
An ammonia levels test measures the amount of ammonia in a sample of your blood. Ammonia is also called NH3. It is a normal waste product in your body. Healthy bacteria in your intestines make ammonia when you digest protein in the foods you eat. Normally, your liver changes ammonia into another waste product called urea. Your kidneys get rid of urea in urine (pee). This process is called the urea cycle. When you're healthy, the urea cycle prevents ammonia from building up in your blood. This is very important because ammonia is toxic (poisonous) to your brain. Even small increases in the level of ammonia in your blood can cause permanent brain damage, coma , and even death. Liver disease is the most common cause of high ammonia levels. Other causes include kidney failure and genetic disorders called urea cycle disorders. The medical term for high ammonia levels is hyperammonemia. Other names: NH3 test, blood ammonia test, serum ammonia, ammonia; plasma
Why is this test ordered? You may need this test if you have symptoms that could be from too much ammonia in your blood. The symptoms depend on how high your ammonia levels are and your age. Symptoms in children and adults may include: Feeling irritable Lack of energy and mental alertness or being very sleepy Vomiting Headache Loss of muscle coordination that may cause difficulties with walking or speech Changes in behavior Confusion, including not being sure about the time and/or where or who you are Mood swings Seizures Other symptoms in children may include: Not growing taller or gaining weight as expected Lack of muscle tone (limp muscles) Developmental delays in children or infants Newborn babies may develop symptoms of high ammonia levels within three days after birth. Symptoms in newborns include the above symptoms and may also include fast breathing and/or making grunting sounds when breathing. If your baby or child has any symptoms of high ammonia levels, contact their provider right away. If you have a family history of genetic urea cycle disorders, you or your child may need this test even if you don't have symptoms. If you've been diagnosed with high ammonia levels, you may need this test to see how well your treatment is working.
Clinical Interpretation
Your provider will use your test results, symptoms, and medical history to understand what your ammonia levels say about your health. Normal levels vary with age, but in general, low levels are normal and healthy. If your test results are normal , your provider will order other tests to find out what's causing your symptoms. If your test results show ammonia levels that are higher than normal , it usually means that your body is having trouble getting rid of ammonia. Many types of health conditions can cause high ammonia levels, including: Liver diseases, such as cirrhosis or hepatitis Hepatic encephalopathy Kidney disease or kidney failure Certain genetic disorders, including urea cycle disorders Reye syndrome (most common in in children and teens) Taking certain medicines If the results of an ammonia levels test are high, more tests will usually be done to diagnose the cause. Treatment will depend on the condition that's causing the problem. If you have questions about your test results or treatment, talk with your provider. Learn more about laboratory tests, reference ranges, and understanding results .
Clinical Protocol & Patient Advice
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Your provider will give you specific instructions about how to prepare for an ammonia levels test. You should not smoke for several hours before the test. You may be asked to avoid strenuous exercise and alcohol for a period of time. You may also need to fast (not eat or drink) for several hours. Your provider may tell you to stop taking certain medicines, including diuretics (water pills) and opioid pain medicines. But never stop taking any prescription medicines without talking with your provider first. Babies do not need any special preparations before the test.
Usage Guidance
- Reference ranges vary by laboratory. Always discuss your specific results with a qualified healthcare professional.
Source: MedlinePlus, National Library of Medicine. View the original.