Gallstone Diagnosis: Ultrasound, MRCP & Blood Tests Explained

Gallstone diagnosis uses clinical assessment, blood tests, and imaging. Blood tests: LFTs (elevated bilirubin = bile duct obstruction; elevated ALP/GGT = biliary disease), FBC (elevated WBC = infection), amylase/lipase (elevated = pancreatitis), CRP (elevated = inflammation). Abdominal ultrasound: first-line investigation, >95% sensitivity for gallbladder stones, safe (no radiation), inexpensive, 10-15 minutes. Detects stones, wall thickening, pericholecystic fluid, CBD dilatation. Limitation: small CBD stones may be missed. MRCP: gold standard for bile duct stones (>95% sensitivity), no radiation, 30-45 minutes, recommended when CBD dilatation or obstruction suspected. CT scan: used for pancreatitis severity, cancer suspicion, perforation, or inconclusive ultrasound. Endoscopic ultrasound (EUS): most sensitive for small CBD stones, used when MRCP inconclusive.