What tests and orders should be done for an adult patient with upper abdominal left side pain, considering their age, sex, and past medical history?

Upper Left Abdominal Pain: Diagnostic Workup

For an adult patient presenting with upper left abdominal pain, order a complete blood count, comprehensive metabolic panel including liver function tests and lipase, urinalysis, and pregnancy test (if female of reproductive age), followed by CT scan with IV contrast as the primary imaging modality unless specific clinical features suggest an alternative approach. 1, 2

Initial Laboratory Testing

Mandatory baseline labs include:

• Complete blood count to assess for leukocytosis indicating infection or inflammation 1
• Comprehensive metabolic panel with liver function tests (AST, ALT, alkaline phosphatase, bilirubin) to evaluate hepatobiliary and pancreatic pathology 1, 2
• Serum lipase (superior to amylase for pancreatic pathology with better sensitivity and specificity) 3, 4, 5
• Urinalysis to evaluate for urinary tract infection or nephrolithiasis 1
• Beta-hCG in all women of reproductive age before any imaging to prevent unnecessary fetal radiation exposure and avoid missing ectopic pregnancy 1, 2

Additional labs to consider based on clinical context:

• C-reactive protein as a marker of inflammation, particularly if considering pancreatitis (levels >150 mg/L indicate need for imaging to detect complications) 3
• Serum triglycerides if pancreatitis is suspected, as hypertriglyceridemia is a notable cause 3, 4

Imaging Strategy

CT scan with IV contrast is the primary imaging modality for upper left quadrant pain when the diagnosis is unclear from history, physical examination, and laboratory testing 6, 2. CT has 89% sensitivity for urgent abdominal conditions and can identify specific pathology including pancreatitis, splenic pathology, and bowel perforation 7.

Alternative imaging considerations:

• Abdominal ultrasound may be considered first if biliary colic characteristics are present (though this typically causes right upper quadrant pain, pain can occasionally radiate or be atypical) 6
• MRI without and with contrast is an alternative in patients with contraindications to CT contrast (severe renal disease with eGFR <30 mL/min/1.73m², contrast allergy) 6
• Upright chest radiograph if pneumoperitoneum (bowel perforation) is suspected based on peritoneal signs, though CT is more sensitive (89% vs 49%) 7

Critical Clinical Considerations

Key history elements that guide workup:

• Radiation to the back suggests pancreatitis 3, 4
• Fever raises concern for infection, abscess, or inflammatory processes and warrants blood cultures if sepsis is suspected 1
• Diarrhea may indicate infectious or inflammatory bowel disease 1
• Hemodynamic instability requires immediate surgical consultation rather than extended workup 1

Physical examination priorities:

• Assess for peritoneal signs (guarding, rebound tenderness) which indicate need for urgent imaging 6
• Check for resonant liver percussion note which indicates pneumoperitoneum 7
• Perform cardiovascular examination if considering mesenteric ischemia 1

Common Pitfalls to Avoid

• Never proceed with CT imaging in reproductive-age women without pregnancy testing, as this leads to delayed diagnosis of ectopic pregnancy and unnecessary fetal radiation exposure 1, 2
• Do not routinely order conventional radiography as it has limited diagnostic value (49% sensitivity for bowel obstruction) and rarely changes management 7, 1
• Do not assume normal initial labs exclude serious pathology in patients with high clinical suspicion—proceed to appropriate imaging 1
• In immunocompromised patients, maintain a lower threshold for extensive workup as presentation may be atypical 1
• Do not delay imaging in clinically deteriorating patients while pursuing additional non-diagnostic tests 1

Specific Diagnostic Considerations for Left Upper Quadrant

While upper left quadrant pain is less commonly addressed in guidelines compared to other quadrants, the differential includes:

• Pancreatitis (most important to rule out): Diagnosed with 2 of 3 criteria: upper abdominal pain radiating to back, lipase/amylase ≥3× upper limit of normal, and/or CT/MRI findings 3, 4, 5
• Splenic pathology (infarction, rupture, abscess): Requires CT imaging for diagnosis 2
• Gastric pathology: Consider if dyspepsia symptoms present 6
• Bowel perforation: CT is most sensitive imaging modality 7
• Diverticulitis (though typically left lower quadrant, can occasionally present higher): CT has >95% sensitivity 6

The workup should be expedited if the patient has alarm features: age >60 years with weight loss (consider urgent CT), peritoneal signs, or hemodynamic instability 6, 1.