What preoperative labs are recommended for emergency surgery?

Preoperative Laboratory Testing for Emergency Surgery

For emergency surgery, preoperative testing should include COVID-19 screening, basic metabolic panel, complete blood count, coagulation studies, and electrocardiogram for patients with cardiovascular risk factors, while avoiding unnecessary routine testing that could delay urgent intervention. 1

COVID-19 Screening in Emergency Setting

For emergency surgical cases that cannot be delayed, the following approach is recommended:

• Assume COVID-19 positive status until proven otherwise 1
• Perform rapid COVID-19 diagnostic testing if available 1
• Obtain chest imaging (X-ray, CT scan, or lung ultrasound) based on availability 1
• For immediate surgery (TACS class 1 or 2), proceed without waiting for RT-PCR results 1

Essential Preoperative Laboratory Tests

Blood Tests

• Complete Blood Count (CBC)

  • Indicated for patients with history of anemia, recent blood loss, or anticipated significant blood loss 2
  • Essential for emergency procedures with potential for major blood loss

• Basic Metabolic Panel/Electrolytes

  • Indicated for patients:
    • Taking diuretics, ACE inhibitors, or ARBs 1, 2
    • With known renal disease 1, 2
    • Undergoing major emergency surgery 1

• Coagulation Studies

  • Indicated for patients:
    • On anticoagulant therapy 2
    • With history of bleeding disorders 2
    • With liver disease 2
    • Undergoing procedures with high bleeding risk 3

• Type and Screen/Cross

  • Not routinely needed for low-risk procedures (e.g., appendectomy, cholecystectomy, hernia repair) 4
  • Indicated for procedures with anticipated blood loss >500 mL 2
  • Reserve for emergency procedures with high bleeding risk

Cardiac Assessment

• 12-lead ECG
  • Recommended for patients with:
    • Known coronary heart disease or structural heart disease 1
    • Age >65 years 1
    • Cardiovascular risk factors (diabetes, hypertension, etc.) 1
  • Not indicated for asymptomatic patients undergoing low-risk procedures 1

Risk-Based Approach to Testing

Rather than ordering routine tests for all emergency surgical patients, follow this algorithm:

1. Assess surgical urgency:

   • For immediate life-threatening conditions (TACS class 1-2), obtain only essential tests that would impact intraoperative management 1
   • For less urgent cases, more comprehensive testing may be appropriate

2. Evaluate patient risk factors:

   • Age >65 years
   • Cardiovascular disease
   • Renal disease
   • Liver disease
   • Bleeding disorders
   • Medication use (anticoagulants, diuretics, etc.)

3. Consider surgical risk:

   • High-risk procedures (major blood loss potential)
   • Intermediate-risk procedures
   • Low-risk procedures

Common Pitfalls to Avoid

• Overreliance on routine testing increases costs and may delay emergency surgery without improving outcomes 5
• Outdated testing (>2 months old) may not reflect current patient status and is associated with increased complications 6
• Unnecessary type and screen for low-risk procedures wastes resources and doesn't improve care 4
• Delaying emergency surgery for non-essential test results can worsen patient outcomes

Important Considerations

• Laboratory tests performed within 2 months of surgery are generally acceptable for stable patients 6
• In Japan, despite recommendations against routine testing, approximately 60% of low-risk surgeries still receive preoperative blood tests 7
• The goal of preoperative evaluation is not to give "medical clearance" but to assess current medical status and provide risk profile 2

By following this evidence-based approach to preoperative testing in emergency surgery, clinicians can ensure patient safety while avoiding unnecessary delays and resource utilization.