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In the body, if the liver is not able to convert ammonia into urea, the ammonia levels in the blood will increase and can be caused by cirrhosis or severe hepatitis. Therefore, to determine this indicator, doctors will use a quantitative test of ammonia in the blood.
1. What is blood ammonia?
Ammonia (NH3) is a compound produced during the body's protein metabolism, this is a waste product, normally transported to the liver for conversion to urea and glutamine, which is then excreted in water. urine.
In the body, under normal conditions, Ammonia will be converted into urea by the liver and then excreted by the kidneys. If a physical disorder prevents this conversion from happening, ammonia will build up in the circulation and cause hepatic encephalopathy and loss of normal liver function. Brain.
Once liver function is impaired due to disorders, ammonia and other metabolites in the liver can accumulate in the brain to cause psychological and neurological changes, which can even lead to death. death in patients.
2. Why do a quantitative ammonia blood test?
A quantitative blood ammonia test (NH3 test) is used to measure the amount of ammonia in the blood.
In the body, ammonia is formed when proteins are broken down and converted by the liver to urea, which is then excreted in the urine. However, when the liver is not able to convert ammonia into urea, it results in elevated blood ammonia levels.
In neonates, elevated blood ammonia may be due to a deficiency of the enzyme in the urea cycle or acute liver disease. In adults, elevated blood ammonia levels can be caused by liver-related diseases, azotemia syndrome, gastrointestinal bleeding, heart failure, or pericarditis.
Quantitative Ammonia blood test plays an important role in providing information to diagnose encephalopathy and some liver-related diseases.
Alternatively, the NH3 blood test can be used to predict the presence of Reye's syndrome or to predict a genetic deficiency in the urea cycle.
A blood ammonia level test can also be used to find out what causes lethargy and unexplained vomiting in young children.
Xét nghiệm định lượng ammoniac trong máu được dùng để đo lường lượng amoniac trong máu
3. Steps to take samples for NH3 blood test
Patients are asked not to eat or drink anything other than water, not to smoke for 8 hours, not to exercise and have strenuous physical activities before taking blood for testing.
To avoid erroneous results of NH3 blood test, patients or family members need to provide information about their current medications, inform about their smoking or alcohol use. Talk to your doctor about any test-related concerns or concerns
Blood ammonia samples are plasma and blood that has been anticoagulated with EDTA. Specimens need to be placed in a blood tube and stored on ice and then quickly transported to the laboratory.
Procedure for taking a blood sample for ammonia quantification:
Taking a specimen from a vein: The medical staff will use an elastic band wrapped around the arm to make the veins larger, convenient for needle insertion into a vein. Disinfect the blood collection site with alcohol and use a needle to draw blood. When the blood sample has been collected enough, the medical staff will remove the elastic band and place the cotton on the blood collection site. Venous blood sampling may cause a small bruise at the site of the blood draw. Although very rare, it is still possible for a vein to swell after a blood sample is taken. Arterial specimen collection: The medical staff will use a needle to draw blood from the inside of the patient's wrist, elbow, or groin. It should be ensured that the blood flow into the test tube is normal and that no damage to the carpal artery occurs when the blood sample is taken. The steps will be done in the same way as for venipuncture. Similar to the venipuncture procedure, an arterial blood draw may also produce a small bruise at the site of the needle puncture. Some people may feel light-headed, dizzy, or nauseous while blood is drawn from an artery. In rare cases, it can damage nerves or arteries and cause blockages. After blood collection, physical activity or exertion should be avoided for 24 hours.
4. Indication for a quantitative test of ammonia in the blood
Quantitative testing of ammonia in the blood is indicated for the following cases:
Used to check the functioning of the liver; Used to evaluate the course of treatment for patients with severe liver disease such as cirrhosis; Used for the diagnosis/prognosis of Reye's syndrome which may damage the liver and brain or for the prognosis of acute liver failure. Used to test ammonia levels in a recipient of nutritional (IV) infusion. Normal reference values for a quantitative blood ammonia test include:
For adults, values range from 15-45 ug/dL or 11-32 umol/L; In children, values range from 40 to 80 ug/dL or 28 to 57 umol/L; For infants, values range from 90 to 150 ug/dL or 64 to 1072 umol/L.
5. Notes when conducting Ammonia blood test
The following factors can contribute to erroneous results of the blood ammonia test:
Some drug effects can increase or decrease blood ammonia levels such as: Heparin phenelzin, tranylcypromine, and lactulose, etc... The patient has a habit of smoking; The patient has exercised or exerted too much force; The patient has a high or low protein diet; Ammonia present in the air can artificially raise test results. Cellular metabolism can also increase ammonia levels from 20% within 1 hour and 100% within 2 hours. If you want to get accurate results, you need to go to a reputable medical facility with modern equipment to conduct a quantitative ammonia blood test. Currently, the Laboratory - Vinmec International General Hospital is one of the leading prestigious addresses in the country, trusted by many patients. Thanks to the use of modern machines and equipment to check and analyze patient samples, it has provided accurate information and indicators, helping doctors to assess the general health status of patients. testing, early detection of disease and timely treatment suggestions. In particular, with a space designed according to 5-star hotel standards, Vinmec guarantees to bring patients the most comfort, friendliness and peace of mind when visiting and receiving treatment at the hospital.
Please dial HOTLINE for more information or register for an appointment HERE. Download MyVinmec app to make appointments faster and to manage your bookings easily.
