From the Guidelines
Elevated Alanine Transaminase (ALT) in a teenage woman is most likely caused by hepatocyte injury, which can be due to various factors such as nonalcoholic fatty liver disease (NAFLD), viral hepatitis, medication effects, autoimmune hepatitis, or alcohol consumption, as indicated by the most recent study 1.
Causes of Elevated ALT
The causes of elevated ALT can be categorized into several groups, including:
- Hepatocellular injury, which can be caused by viral hepatitis, medication effects, or autoimmune hepatitis
- Nonalcoholic fatty liver disease (NAFLD), which is a spectrum of fat deposition and hepatic inflammation followed by fibrosis due to metabolic insults
- Alcohol-induced liver disease, which is caused by excess alcohol consumption
- Genetic conditions, such as alpha1-antitrypsin deficiency, hemochromatosis, and Wilson disease
- Other causes, such as celiac disease, muscle disorders, and ischemic hepatitis
Normal ALT Values
Normal ALT values typically range from 7-55 U/L for females, though reference ranges may vary slightly between laboratories 1.
Evaluation of Elevated ALT
If a true elevation of ALT is present, further evaluation is needed to determine the underlying cause. This may include additional laboratory tests, imaging studies, and a thorough medical history and physical examination.
Importance of ALT in Liver Function
ALT is an enzyme primarily found in liver cells that leaks into the bloodstream when liver cells are damaged. It is a sensitive indicator of liver cell damage and is often used as a screening test for liver disease.
Limitations of ALT as a Screening Tool
While ALT is a useful screening tool for liver disease, it has limitations. For example, a negative screening result does not exclude the presence of NAFLD, and no conclusion on inflammation or fibrosis can be made based on ALT levels alone 1.
Clinical Approach
In clinical practice, a comprehensive approach is needed to evaluate elevated ALT, including a thorough medical history, physical examination, and additional laboratory tests and imaging studies as needed. The most important step is to identify and address the underlying cause of the elevated ALT, as indicated by the most recent study 1.
From the FDA Drug Label
WARNINGS Liver warning: This product contains acetaminophen. Severe Liver damage may occur if you take • more than 6 caplets in 24 hours, which is the maximum daily amount • with other drugs containing acetaminophen • 3 or more alcoholic drinks everyday while using this product
The FDA drug label suggests that elevated Alanine Transaminase (ALT), indicating liver damage, may be caused by:
- Taking more than the recommended dose of acetaminophen
- Taking acetaminophen with other drugs containing acetaminophen
- Consuming 3 or more alcoholic drinks everyday while using acetaminophen 2
From the Research
Causes of Elevated Alanine Transaminase (ALT) Levels
Elevated ALT levels in a teenage woman can be caused by various factors, including:
- Metabolic dysfunction-associated steatotic liver disease (MASLD) and alcoholic liver disease, which are the most common causes of mildly elevated transaminase levels 3, 4, 5
- Uncommon causes such as drug-induced liver injury, chronic hepatitis B and C, and hereditary hemochromatosis 3, 4, 5
- Rare causes including alpha1-antitrypsin deficiency, autoimmune hepatitis, and Wilson disease 3, 4, 5
- Extrahepatic causes such as celiac disease, hyperthyroidism, rhabdomyolysis, and pregnancy-associated liver disease 3, 4, 6
- Adrenal insufficiency, which is a rare endocrine disorder that can cause liver involvement and elevated liver enzymes 7
Evaluation of Elevated ALT Levels
The evaluation of elevated ALT levels should include:
- Initial laboratory testing to assess complete blood cell count with platelets, blood glucose, lipid profile, hepatitis B surface antigen, hepatitis C antibody, serum albumin, iron, total iron-binding capacity, and ferritin 3, 4, 5
- Non-invasive serologic tests to exclude hepatic diseases such as chronic hepatitis B and C, autoimmunhepatitis, non-alcoholic steatohepatitis, hemochromatosis, Wilson-disease, and celiac sprue 6
- Ultrasound, mini-laparoscopy, and liver biopsy may be necessary to establish a final diagnosis if non-invasive serologic studies remain inconclusive 6
- A trial of lifestyle modification with observation or further testing for less common causes may be appropriate if initial test results are normal 4, 5