Laboratory Testing for Right Upper Quadrant Abdominal Pain
Order a complete metabolic panel including liver function tests (AST, ALT, alkaline phosphatase, bilirubin) as the essential initial laboratory workup for right upper quadrant pain. 1
Core Laboratory Panel
The following labs should be obtained immediately for any patient presenting with RUQ pain:
- Comprehensive Metabolic Panel (CMP) including liver enzymes and bilirubin levels to assess for hepatobiliary pathology 1
- Complete Blood Count (CBC) to evaluate for leukocytosis suggesting infection or inflammation 2
- Lipase to assess for pancreatitis, which can present with RUQ pain 2
- C-reactive protein (CRP) as an inflammatory marker that helps guide workup 2
- Urinalysis to exclude urinary tract infection or urolithiasis as alternative diagnoses 2
- Beta-hCG (pregnancy test) in all women of reproductive age before any imaging, as this is critical to avoid missing ectopic pregnancy and guides imaging choices 3, 2
Interpretation of Liver Function Tests
Elevated bilirubin, alkaline phosphatase, or transaminases indicate potential biliary obstruction or cholestasis and necessitate anatomic visualization of the bile ducts with imaging. 1, 4
- Elevated liver enzymes suggest hepatobiliary pathology requiring ultrasound as the next step 1
- If ultrasound demonstrates biliary dilatation with elevated LFTs, proceed directly to MRCP rather than additional laboratory testing 4
- Normal liver enzymes do not exclude biliary pathology, as acute cholecystitis can present with normal labs, particularly in early disease 2
Critical Clinical Pitfalls
Do not delay imaging while waiting for laboratory results in patients with peritoneal signs or hemodynamic instability. 2
- Laboratory testing should complement, not replace, appropriate imaging—ultrasonography remains the initial imaging test of choice for RUQ pain regardless of lab values 3, 1
- Elderly and immunocompromised patients may present with normal laboratory values despite serious infection, requiring a lower threshold for imaging 5
- Anorexia and other nonspecific symptoms have little predictive value and should not guide laboratory ordering decisions 6
Additional Considerations Based on Clinical Context
- If pain occurs specifically during bowel movements, consider that this suggests colonic or mechanical causes rather than primary hepatobiliary disease, which typically presents with postprandial pain 1
- Electrolytes, creatinine, and glucose should be included in the initial workup as part of the comprehensive metabolic panel 2
- Point-of-care testing can expedite diagnosis, but formal laboratory confirmation is still recommended 2