From the Guidelines
Liver Function Test (LFT) results should be interpreted with caution, considering the context and clinical presentation of the patient.
Interpretation of LFT Results
The interpretation of LFT results requires an understanding of the biochemical markers of hepatocyte damage or bile flow, which indicate hepatobiliary insult rather than a measurement of liver function 1.
- Hepatocellular predominant abnormal LFTs are reflected as an increase in aminotransferases, such as alanine transaminase (ALT) and aspartate transaminase (AST), which are indicative of liver damage 1.
- ALT elevations are specific for liver injury, whereas AST elevations can be due to disorders involving other organs, such as the heart, skeletal muscle, kidneys, brain, and red blood cells 1.
- The severity of abnormal aminotransferase can be classified as mild, moderate, or severe, based on the upper reference limit 1.
Clinical Context
The interpretation of abnormal LFT results requires consideration of the clinical context, including the patient's medical history, symptoms, and other laboratory results 1.
- Cholestatic liver disease can be suspected if alkaline phosphatase (ALP) is elevated, with or without elevated bilirubin 1.
- Liver blood tests should be interpreted in conjunction with other laboratory results, such as bilirubin, albumin, international normalized ratio (INR), and platelet count, to assess liver function and fibrosis 1.
Management
The management of abnormal LFT results depends on the underlying cause and severity of the liver disease 1.
- Non-alcoholic fatty liver disease (NAFLD) and liver disease of unknown etiology require further evaluation, including calculation of FIB-4 or NAFLD fibrosis score, and consideration of imaging modalities, such as ARFI elastography/FibroScan 1.
- Referral to a hepatology clinic may be necessary for assessment and management of liver disease, including screening and treatment of portal hypertension and hepatocellular carcinoma (HCC) screening and management 1.
From the Research
Interpretation of Liver Function Test (LFT) Results
The interpretation of LFT results is crucial in assessing and monitoring liver diseases. According to 2, LFTs are a panel of blood markers used to evaluate liver function, but they are not all true tests of liver function, and abnormalities may not reflect liver disease.
Role of LFTs in Detecting Hepatic Dysfunction
LFTs are helpful screening tools to detect hepatic dysfunction, as stated in 3 and 4. They can be used to categorize hepatic dysfunctions, estimate the severity of hepatic disease, and monitor liver diseases. However, no single test is sufficient alone to provide a complete estimate of liver function, as the liver performs a variety of functions.
Challenges in Interpreting LFT Results
Interpreting LFT results can be challenging, as abnormalities may not always reflect liver disease, and many tests are not specific for the liver, as mentioned in 5 and 6. A careful history, clinical examination, and interpretation of the pattern of liver test abnormalities are necessary to identify the type and etiology of liver disease.
Key Considerations in LFT Interpretation
Some key considerations in interpreting LFT results include:
- Knowledge of underlying pathophysiology and the characteristics of panel tests, as stated in 3
- Classification of liver diseases, which are commonly detected by routine LFT, as mentioned in 3
- Use of composite scores, such as the Model for End Stage Liver Disease, to assess the severity of liver injury, as recommended in 6
- Awareness that many commonly performed markers are not specific for the liver and can be affected by various factors unrelated to liver disease, as noted in 6