From the Guidelines
Chronic liver function test (LFT) elevation is typically defined as persistent abnormalities lasting for more than 6 months. If LFTs remain elevated for this duration, further evaluation is warranted to determine the underlying cause, as stated in the american gastroenterological association medical position statement 1. The specific threshold for concern depends on the degree of elevation, with mild elevations (less than 2-3 times the upper limit of normal) sometimes being monitored, while more significant elevations require prompt investigation regardless of duration.
Key Considerations
- Common causes of chronic LFT elevation include non-alcoholic fatty liver disease, alcoholic liver disease, viral hepatitis, autoimmune hepatitis, and medication-induced liver injury.
- The pattern of elevation can provide diagnostic clues - predominant elevations in AST and ALT suggest hepatocellular injury, while elevated alkaline phosphatase and GGT point toward cholestatic processes.
- Patients with chronic LFT elevations should undergo comprehensive evaluation including detailed history, physical examination, and appropriate laboratory and imaging studies to identify the underlying etiology and prevent progression to advanced liver disease.
Monitoring and Evaluation
According to the british thoracic society guideline 1, baseline liver function tests (LFTs) should be checked prior to initiating certain therapies, and LFTs should be checked after 1 month of treatment and then every 6 months thereafter for the duration of therapy. However, the definition of chronic LFT elevation is based on the duration of elevation, not the frequency of monitoring.
Clinical Implications
In clinical practice, it is essential to evaluate patients with elevated LFTs in the context of all clinical information, as stated in the american gastroenterological association medical position statement 1. If LFTs remain elevated for more than 6 months, further evaluation is necessary to determine the underlying cause and prevent progression to advanced liver disease.
From the Research
Definition of Chronic LFT Elevation
There is no specific definition of the duration for which Liver Function Tests (LFTs) need to be elevated to be considered chronic. However, the following points can be considered:
- Elevated liver enzymes are a frequent finding in both symptomatic and asymptomatic patients, necessitating further evaluation to clarify the underlying disease 2.
- A study found that about 50% of individuals who had alanine aminotransferase (ALT) and gamma-glutamyl transferase (GGT) at the top quintile at baseline continued to remain so with high values after 12 years 3.
- Mild, asymptomatic elevations of alanine transaminase and aspartate transaminase levels are common in primary care, and it is estimated that approximately 10% of the U.S. population has elevated transaminase levels 4.
Patterns of LFT Elevation
The following patterns of LFT elevation can be defined:
- A predominant increase in transaminase activities reflects a disturbance of hepatocellular integrity, which can be found in patients with viral hepatitis, genetic liver diseases, and drug-induced liver diseases 2.
- A second pattern is characterized by high serum alkaline phosphatase and γ-glutamyltranspeptidase activities, indicating cholestatic liver diseases 2.
- A third enzym pattern is defined by a predominant rise in γ-glutamyl transpeptidase, which is observed in alcoholic or non-alcoholic fatty liver disease and infiltrating liver diseases 2.
Evaluation and Management
The evaluation and management of elevated LFTs should be guided by both the clinical presentation and the pattern of injury, and may include: