Ammonia Test

An ammonia test is advised:

• To diagnose hepatic encephalopathy
• To check the functioning of liver if any symptom of mental confusion is present
• To check the success of treatment of liver diseases
• To diagnose Reye syndrome (a childhood disorder that affects the liver and brain)
• To predict the prognosis of Reye syndrome
• To determine/predict the prognosis of acute liver failure
• To determine ammonia level when high-calorie intravenous nutrition is taken

An ammonia test can be recommended in infants if they show the following symptoms:

• Vomiting
• Irritability
• Seizures
• Lethargy

It can also be advised in a child who has been diagnosed with a viral illness, such as influenza or chickenpox and has been showing the above symptoms for about a week.

Do not eat or drink anything for about eight hours prior to the test. Do not exercise, smoke or drink alcohol before the test.

Inform your doctor if you are on any medications or supplements. He/she may advise you to stop taking certain medicational drugs that can alter test results. These include alcohol, acetazolamide, barbiturates, narcotics, diuretics and valproic acid.

It is a simple test, in which, a blood sample is collected by drawing blood from a vein in the arm. The sample is collected in a sterile vial or a test tube and sent to a laboratory for analysis. The injection site is pressed firmly, and a cotton ball or gauze pad is placed over that area.  A momentary pricking pain is felt when the needle goes in the vein.

There is a minimal risk of light-headedness and bruising at the site of injection. However, at most times, these symptoms disappear quickly. Rarely, an infection may occur at the site of withdrawal of blood.

Results of an ammonia test can vary depending upon the method used and the age, gender, and past health history of the person. A doctor will provide the correct interpretation of your results.

Normal results: Normal range of blood ammonia levels for various age groups are mentioned below:

• Adults: 10-80 micrograms per decilitre (mcg/dL)
• Children (older than 2 years): 19-60 mcg/dL
• Infants and toddlers (10 days to 2 years): 68-136 mcg/dL
• Age (0-10 days): 170-341 mcg/dL

Abnormal results: An abnormal result usually means you have an increased level of ammonia in the blood. It can be due to the following conditions:

• Liver failure
• Liver diseases (cirrhosis or hepatitis)
• Low blood potassium level (in people with liver disease) (Read more: Potassium deficiency symptoms)
• Reye syndrome
• Heart failure
• Kidney failure
• Salicylate poisoning
• Severe gastrointestinal (GI) bleeding, usually in the upper GI tract
• Genetic diseases of the urea cycle
• Parenteral nutrition (nutrition by vein)
• Hyperthermia (high body temperature)
• Kidney disease
• Severe muscle exertion
• Ureterosigmoidostomy (a procedure in which ureters are converted into a sigmoid colon)
• Urinary tract infection caused due to a bacteria called Proteus mirabilis.

In infants, a high concentration of ammonia can be an indication of an inherited urea cycle enzyme deficiency or haemolytic disease of the newborn.

A reduced level of ammonia can be seen in essential or malignant hypertension. Essential hypertension does not have any known cause, whereas malignant hypertension occurs very quickly with very high blood pressure and may occur due to vascular conditions, kidney diseases or as a result of missing blood pressure medicines.

Disclaimer: All results must be clinically correlated with the patient’s complaints to make a complete and accurate diagnosis. The above information is provided from a purely educational point of view and is in no way a substitute for medical advice by a qualified doctor.