Elevated Liver Function Tests: Explanation and Management

Introduction to Liver Function Tests

The American College of Radiology suggests that liver function tests (LFTs) detect liver cell injury or bile flow problems, not liver function itself 1
LFTs are misleadingly named, as they primarily detect damage to liver cells or blockages in bile flow, rather than measuring the liver's ability to perform its essential functions 1

The American College of Radiology recommends recognizing two main patterns of liver damage: hepatocellular and cholestatic 1
In the hepatocellular pattern, ALT and AST are elevated much higher than alkaline phosphatase, indicating liver cell injury 1
In the cholestatic pattern, alkaline phosphatase is elevated more than ALT/AST, suggesting bile flow problems 1

The American College of Radiology classifies LFT elevations as mild (<5 times the upper normal limit), moderate (5-10 times normal), or severe (>10 times normal) 1, 3
Life-threatening elevations are defined as greater than 20 times normal, requiring immediate hospitalization 3

The American College of Radiology identifies fatty liver disease, alcohol-related liver disease, viral hepatitis, and medications as common causes of elevated LFTs 1, 3
Fatty liver disease is the most common cause, often associated with obesity, diabetes, or metabolic syndrome 1, 3

For mild elevations, the American College of Radiology recommends monitoring weekly until values normalize, eliminating potential causes, and rechecking in 3-6 months if initial workup is unrevealing 3
For moderate to severe elevations, immediate workup for viral hepatitis, autoimmune disease, and imaging studies is necessary, with monitoring every 2-3 days until stable or improving 3
For life-threatening elevations, immediate hospitalization is required for intensive monitoring 3

The American College of Radiology recommends additional testing, including blood work, ultrasound, and fibrosis assessment, to determine the underlying cause of elevated LFTs 3, 2
Ultrasound is essential to look for fatty liver, masses, bile duct blockage, and assess liver texture 3, 2

The American College of Radiology recommends referring patients to hepatology for persistent unexplained elevations, ALT greater than 5 times normal, evidence of advanced fibrosis, or signs of liver failure 3, 4, 1