From the Guidelines
Elevated alkaline phosphatase (ALP) and alanine aminotransferase (ALT) levels in blood tests suggest liver dysfunction or disease that requires medical evaluation, and you should consult a healthcare provider promptly for proper diagnosis and treatment. These elevated enzymes can indicate various conditions including viral hepatitis, alcoholic liver disease, non-alcoholic fatty liver disease, medication-induced liver injury, biliary obstruction, or autoimmune liver disorders 1. Your doctor will likely order additional tests such as a comprehensive metabolic panel, hepatitis panel, liver ultrasound, and possibly other imaging studies to determine the underlying cause.
While awaiting medical care, it is essential to:
- Avoid alcohol consumption
- Review your medications with your doctor for potential liver-toxic drugs
- Maintain a healthy diet low in processed foods and sugars
- Stay well-hydrated
The liver has remarkable regenerative capacity, and many causes of enzyme elevation can be effectively treated once properly diagnosed. ALP is produced in the liver and bones, with elevation often indicating bile duct problems, while ALT is more specific to liver cell damage. The pattern and degree of elevation can provide clues about the nature and severity of the underlying condition. For instance, a significant increase in ALT levels can be directly linked to hepatocyte injury, and common causes include nonalcoholic fatty liver disease (NAFLD) and alcohol-induced liver disease 1.
In cases of elevated ALP, it is crucial to consider the possibility of cholestatic liver disease, which can be due to obstruction of biliary outflow or impairment in bilirubin uptake 1. The severity of abnormal aminotransferase can be classified as mild, moderate, or severe, and the approach to evaluation and management may vary depending on the clinical scenario and the presence of other laboratory abnormalities or symptoms 1.
It is also important to consider other liver disorders, such as genetic/metabolic liver disease, autoimmune hepatitis, Wilson’s disease, or coinfection with other viruses, and conduct testing as appropriate 1. A comprehensive evaluation, including a thorough medical history, physical examination, and laboratory tests, is necessary to determine the underlying cause of elevated ALP and ALT levels and to guide treatment decisions.
From the Research
Implications of Elevated Alkaline Phosphatase (ALP) and Alanine Transaminase (ALT) Levels
- Elevated serum levels of ALP and ALT can indicate liver damage or disease, with ALP levels associated with cholestasis and ALT levels associated with hepatocellular damage 2
- In patients with primary biliary cholangitis (PBC), normal ALP levels are associated with better long-term outcomes, while elevated ALP levels, even within the normal range, can indicate a higher risk of liver-related complications 3, 4
- The ratio of AST to ALT can help distinguish between alcoholic and non-alcoholic liver disease, with a higher ratio often indicating alcoholic liver disease 2
- Elevated ALT levels have been associated with increased liver-related mortality, and a true healthy normal ALT level ranges from 29 to 33 IU/l for males and 19 to 25 IU/l for females 5
- The evaluation of hepatocellular injury includes testing for viral hepatitis, nonalcoholic fatty liver disease, and alcoholic liver disease, while the evaluation of cholestatic injury includes testing for primary biliary cholangitis and primary sclerosing cholangitis 5
- In patients with PBC, an elevated ALP level may still indicate a need for add-on therapy, even in those with a normal GLOBE score 4
- The relative expression of hepatocellular and cholestatic liver enzymes can help identify patients with concurrent forms of liver disease, with predicted ranges of liver enzymes in patients with hepatocellular or cholestatic liver disease providing a useful tool for healthcare providers 6