According to the Mayo Clinic, liver function tests are blood tests that doctors use to determine whether a patient has a damaged or diseased liver. Some of the tests assay the blood levels of certain enzymes that the liver secretes into the blood in response to damage or disease. If these enzymes are at levels that are above normal values, the patient may have liver problems. Liver function tests frequently measure blood levels of the liver enzymes alanine transaminase, or ALT, aspartate transaminase, or AST, and alkaline phosphatase, or ALP.
Hepatitis A
The Mayo Clinic states that a variety of diseases can result in elevated liver enzyme blood levels in a liver function test, including hepatitis A. Hepatitis A is a viral infection of the liver, and people contract it from contaminated food or water or from a person who has the infection, according to the Mayo Clinic. Hepatitis A does not exhibit any symptoms for the first month after infection occurs. Once symptoms do appear, they may include fatigue, nausea and vomiting, abdominal pain on the right side, loss of appetite, dark urine, muscle pain, itching, and yellowing of the eyes and skin. These symptoms persist from two to six months, during which time the body gradually eliminates the virus. There is no specific drug therapy for hepatitis A.
Wilson's Disease
According to Medline Plus, a publication of the National Institutes of Health, and the Mayo Clinic, Wilson's disease is a condition that can cause elevated liver enzyme blood levels in a liver function test. Wilson's disease is a hereditary disorder in which a person's body retains too much of the copper that it ingests. The retained copper accumulates in the liver, brain, kidneys and eyes, and leads to liver and nervous system damage. As stated on the Medline Plus website, Wilson's disease can afflict people of all ancestral origins, but it is particularly prevalent among eastern Europeans, Sicilians and southern Italians. It usually shows up before the age of 40. Symptoms of the disease may include confusion or delirium, dementia, difficulty walking, emotional or behavioral changes, speech impairment, unpredictable movement, vomiting blood, and yellow skin or eyes. Liver function tests will show elevated levels of the liver enzymes ALT and AST.
Nonalcoholic Steatohepatitis
The National Digestive Diseases Information Clearinghouse describes nonalcoholic steatohepatitis as a common liver disease in which fat builds up in the liver, and there is accompanying inflammation and damage. In the early stages of this disease, patients have no symptoms. As the disease progresses and cirrhosis or scarring of the liver develops, patients will experience fatigue, weight loss, and weakness. Elevated blood levels of the liver enzymes ALT and AST, along with MRI or ultrasound studies that show fat deposits in the liver of patients who do not abuse alcohol, will lead a doctor to diagnose nonalcoholic steatohepatitis. The cause of this condition is not clear, but it occurs most frequently in middle-aged, overweight or obese individuals.
Alcoholic Fatty Liver
The American Liver Foundation describes fatty liver as a condition in which excess fat accumulates in liver cells to the point at which fat represents more than 10 percent of the weight of a person's liver. One of the causes of fatty liver is alcohol abuse. Doctors use liver function tests as well as ultrasound, magnetic resonance imaging, and a CT scan to confirm a diagnosis of fatty liver. According to the Hepatitis Central website, fatty liver is the most frequently occurring cause of mild to moderate elevation of the AST and ALT liver enzymes, and alcohol abuse is the most common cause of fatty liver in the United States. Treatment for alcoholic fatty liver involves discontinuing the use of alcohol, lowering serum triglycerides, and increasing physical activity.
References
- MayoClinic.com: Liver Function Tests: Definition: Why It's Done
- MayoClinic.com: Elevated Liver Enzymes: Causes
- MayoClinic.com: Hepatitis A: Definition: Symptoms: Treatment and Drugs
- National Institutes of Health Medline Plus: Wilson's Disease
- National Digestive Diseases Information Clearinghouse: Nonalcoholic Steatohepatitis
