Lfts

LFTs are a group of blood tests used to assess liver injury and function. They help diagnose liver disease, monitor progression, and guide therapy.

The common tests include ALT and AST (hepatocellular enzymes), ALP and GGT (bile duct/ cholestasis markers), bilirubin (total and direct), albumin, and the prothrombin time or INR. Some panels also include alkaline phosphatase isoenzymes or bilirubin fractions.

Interpretation: Elevations of ALT and AST suggest hepatocellular injury; elevated ALP and GGT indicate cholestasis or biliary obstruction; raised bilirubin can cause jaundice, and low albumin or prolonged INR reflect reduced liver synthetic function. The AST/ALT ratio is sometimes informative (AST>ALT with alcohol use; ALT-dominant patterns in fatty liver disease). No single test diagnoses a specific condition.

Limitations: LFTs are not disease-specific and must be interpreted in clinical context. They can be normal in early disease or in chronic liver disease; values are lab-dependent and affected by drugs, pregnancy, and other factors.

If abnormal, clinicians pursue further testing: hepatitis serologies, autoimmune markers, iron and copper studies, imaging (ultrasound, elastography, MRI), and sometimes liver biopsy. In acute overdose (acetaminophen), specific testing is urgent.

Practical notes: LFTs are used for screening, baseline assessment before medications, and monitoring chronic liver disease or response to therapy. Reference ranges vary by lab and patient age.