354 Ch 353. Liver Function, Jaundice, and Approach to Liver Disease

Liver functions：metabolic + synthetic + detoxification + storage + immunological；LFTs (liver function tests)：(1) hepatocellular pattern — AST + ALT ↑; (2) cholestatic pattern — ALP + GGT ↑ ± bilirubin; (3) synthetic dysfunction — albumin, PT/INR；bilirubin metabolism：heme → biliverdin → unconjugated bilirubin → liver conjugation (UGT) → conjugated bilirubin → biliary excretion → urobilinogen → urobilin/stercobilin；jaundice categories：(1) pre-hepatic (hemolysis — unconjugated)；(2) hepatic (hepatocellular dysfunction — mixed; Gilbert syndrome — UGT1A1 mutation, common benign)；(3) post-hepatic / cholestatic (extrahepatic obstruction or intrahepatic cholestasis — conjugated)；approach to abnormal LFT：pattern recognition + clinical context + imaging + serology + biopsy；common etiologies workup：viral hepatitis serology, autoimmune panel, iron/copper studies, alpha-1 antitrypsin, alcohol history, medications；liver elastography (FibroScan) + MR elastography for non-invasive fibrosis assessment；2024 emerging：non-invasive scores (FIB-4, NFS, ELF, vibration-controlled transient elastography) for population screening。