The ammonium - blood test measures the amount of ammonia in a blood sample.
A blood sample is needed. For information on how this is done, see: Venipuncture
Fast for 8 - 12 hours. The health care provider may recommend that you stop taking drugs that may affect your test results.
Drugs that can falsely raise the blood amminia level include alcohol, acetazolamide, narcotics, and valproic acid. A high-protein diet can also raise the blood ammonia level. Talk to your health care provider before this test if you are taking any of these medications.
When the needle is inserted to draw blood, you may feel moderate pain, or only a prick or stinging sensation. Afterward, there may be some throbbing.
This test may be done if you have or are thought to have a condition that may cause a toxic buildup of ammonia. It is most commonly used to diagnose and monitor hepatic encephalopathy, a severe liver disease.
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, lethargy, and sometimes coma.
Berk PD, Korenblat KM. Approach to the patient with jaundice or abnormal liver test results. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 150.
Nevah MI, Fallon MB. Hepatic encephalopathy, hepatorenal syndrome, hepatopulmonary syndrome, and systemic complications of liver disease. In: Feldman L, Friedman LS, Brandt LJ, eds. Sleisenger and Fordtran's Gastrointestinal and Liver Diseases. 9th ed. Philadelphia, Pa: Saunders Elsevier;2010:chap 92.
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