How do you clinically and laboratory-wise diagnose a patient who has passed a gallstone?

Clinical and Laboratory Assessment of Passed Gallstone

To determine if a patient has passed a gallstone, focus on resolution of symptoms (particularly right upper quadrant pain and jaundice), normalization of liver function tests (especially bilirubin and alkaline phosphatase), and imaging confirmation showing decompressed bile ducts without visible stones.

Clinical Assessment

Symptom Resolution

• Relief of biliary colic: The characteristic severe, steady epigastric or right upper quadrant pain that awakens patients from sleep should resolve after stone passage 1
• Resolution of jaundice: If present, visible yellowing of skin and sclera should improve as bilirubin levels normalize 2
• Absence of fever: Temperature should normalize if cholangitis or cholecystitis was present 2
• Negative Murphy's sign: Previously positive focal tenderness over the gallbladder during inspiration should resolve 3

Important Clinical Pitfall

• Pain medication invalidates examination: Administration of analgesics prior to examination makes a negative Murphy's sign unreliable for determining stone passage 3
• Elderly and immunocompromised patients: May not demonstrate typical clinical signs despite ongoing disease 3

Laboratory Assessment

Liver Function Test Normalization

Bilirubin levels are the most specific marker for stone passage:

• Elevated bilirubin (>22.23 μmol/L or >1.3 mg/dL) has 84% sensitivity and 91% specificity for common bile duct stones 2
• Bilirubin >4 mg/dL is a strong predictor of persistent stones 2
• Mean bilirubin in patients with common bile duct stones is typically 1.5-1.9 mg/dL 2
• Normalization of bilirubin strongly suggests stone passage 2

Alkaline phosphatase (ALP) provides supporting evidence:

• ALP >125 IU/L has 92% sensitivity and 79% specificity for common bile duct stones 2
• Normalization of ALP supports stone clearance 2

Transaminases (ALT/AST) are less specific:

• 51% of acute cholecystitis patients without common bile duct stones have elevated ALT 2
• 50% of acute cholecystitis patients without common bile duct stones have abnormal ALT 2
• Transaminase elevation alone is insufficient to determine stone presence or passage 2

Complete panel recommended: ALT, AST, bilirubin, ALP, and GGT should all be measured 2

Imaging Confirmation

Ultrasound as Primary Modality

• Abdominal ultrasound is the initial imaging test of choice with 73% sensitivity and 91% specificity for detecting common bile duct stones 2
• Direct visualization of stone absence in the common bile duct is the strongest predictor that stone has passed 2
• Common bile duct diameter normalization: A diameter <10 mm suggests stone passage, though diameter alone is insufficient (14% of patients with diameter <9.9 mm still have stones) 2

Advanced Imaging When Needed

If clinical suspicion remains despite normal ultrasound and labs:

• MRCP has 93% sensitivity and 96% specificity for common bile duct stones 2
• Endoscopic ultrasound (EUS) has 95% sensitivity and 97% specificity 2
• These modalities definitively confirm stone absence when moderate suspicion persists 2

Algorithmic Approach

Step 1: Clinical Evaluation

• Document resolution of biliary pain, jaundice, and fever 2, 1
• Perform physical examination for absent Murphy's sign (without recent analgesics) 3

Step 2: Laboratory Testing

• Obtain comprehensive liver function tests: ALT, AST, bilirubin, ALP, GGT 2
• Normal bilirubin (<22.23 μmol/L) and normal ALP (<125 IU/L) strongly suggest stone passage 2

Step 3: Imaging Confirmation

• Perform abdominal ultrasound to assess:
  • Absence of visualized common bile duct stone 2
  • Common bile duct diameter <10 mm 2
  • No biliary ductal dilation 2

Step 4: Risk Stratification

If any uncertainty remains, use modified ASGE/SAGES criteria 2:

• Low risk (<10%): Normal labs and imaging—stone likely passed
• Moderate risk (10-50%): Consider MRCP or EUS for definitive confirmation 2
• High risk (>50%): Persistent abnormalities warrant ERCP 2

Critical Caveats

• No single test is sufficient: Combination of clinical, laboratory, and imaging findings provides optimal accuracy 2, 3
• Normal ultrasound doesn't exclude stones: Sensitivity ranges 32-100% depending on stone location and bowel gas interference 2
• Asymptomatic stones: If stone was discovered incidentally, passage determination relies entirely on imaging since symptoms were absent initially 2
• Timing matters: Diagnostic accuracy of bilirubin increases with duration and severity of obstruction 2