Laboratory Tests for Right Upper Quadrant Pain
For patients presenting with right upper quadrant (RUQ) pain, initial laboratory evaluation should include a complete blood count (CBC), liver function tests (LFTs), and pancreatic enzymes to identify the underlying cause. 1
Initial Laboratory Workup
The American College of Radiology recommends the following laboratory tests for RUQ pain:
Complete Blood Count (CBC)
- Evaluates for leukocytosis, which may indicate infection or inflammation
- Particularly important when acute cholecystitis is suspected
Liver Function Tests (LFTs)
- ALT, AST (transaminases) - assess hepatocellular injury
- Alkaline phosphatase, GGT - evaluate for biliary obstruction
- Bilirubin (total and direct) - assess for cholestasis or hemolysis
Pancreatic Enzymes
- Amylase and lipase - rule out pancreatic pathology
Additional Laboratory Tests to Consider
Beta-human chorionic gonadotropin (β-hCG)
- Essential for women of reproductive age to rule out pregnancy before imaging 1
Urinalysis
- To evaluate for urinary tract pathology that may present with RUQ pain
Inflammatory markers
- C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR)
- Particularly useful when infection or inflammation is suspected
Laboratory Tests Based on Clinical Suspicion
For suspected biliary disease:
- Focus on LFTs, particularly alkaline phosphatase and GGT
- Elevated bilirubin may indicate biliary obstruction
For suspected hepatic pathology:
- Complete LFT panel
- Consider viral hepatitis serologies if clinically indicated
For suspected pancreatic disease:
- Lipase is more specific than amylase for pancreatic inflammation
Diagnostic Pitfalls to Avoid
Don't rely solely on laboratory tests
- Normal laboratory values don't exclude significant pathology
- Laboratory abnormalities may be subtle in early disease
Consider non-hepatobiliary causes
- RUQ pain with elevated alkaline phosphatase isn't always hepatobiliary in origin 2
- After negative hepatobiliary workup, consider referred pain from other sources
Avoid premature diagnostic closure
- Over one-third of patients initially thought to have acute cholecystitis actually have RUQ pain from other causes 3
- Consider thoracic, renal, adrenal, and gastrointestinal sources of pain
Follow-up Imaging Considerations
After laboratory evaluation, ultrasonography is recommended as the initial imaging study for patients with RUQ pain due to:
- No radiation exposure
- Cost-effectiveness
- High specificity (83%) for acute cholecystitis
- 96% accuracy for detecting gallstones 1
Laboratory results should guide subsequent imaging decisions, with abnormal LFTs potentially indicating the need for more advanced imaging such as MRCP or cholescintigraphy.