What laboratory workup is recommended for a patient with suspected intussusception?

Laboratory Workup for Intussusception

In suspected intussusception, laboratory testing plays a minimal role in diagnosis, as imaging (ultrasound in children, CT in adults) is the primary diagnostic modality; however, basic labs should be obtained when complications such as bowel ischemia, perforation, or systemic illness are suspected. 1

Primary Diagnostic Strategy

• Ultrasound is the first-line diagnostic tool for suspected intussusception in pediatric patients, offering high diagnostic accuracy without radiation exposure 1
• CT scan is the most sensitive diagnostic modality in adults, with 90.5% accuracy for detecting intussusception and distinguishing between cases with and without a lead point 2, 3
• Laboratory tests are not routinely required for diagnosis but serve to assess complications and guide perioperative management 4, 2

Laboratory Testing Indications

When to Order Labs

Order laboratory tests in the following clinical scenarios:

• Patients presenting with signs of bowel obstruction (present in 70.7% of adult intussusception cases) 3
• Suspected bowel ischemia or perforation based on clinical examination 5
• Systemic signs of infection or sepsis (fever, hemodynamic instability) 5
• Preoperative assessment once surgical intervention is planned 4

Specific Laboratory Tests to Consider

Complete Blood Count (CBC):

• Check for anemia, which is an independent predictor of malignancy in adult intussusception (particularly in colonic cases where 69% are malignant) 4
• Leukocytosis may indicate bowel ischemia or transmural necrosis, though it can be absent in immunocompromised patients 5

Inflammatory Markers:

• C-reactive protein (CRP), procalcitonin (PCT), and lactate levels should be obtained when systemic infection or bowel ischemia is suspected 5
• These markers help assess severity of illness and guide management decisions 5

Basic Metabolic Panel:

• Serum creatinine and electrolytes should be checked in patients with signs of systemic illness or those requiring surgery 5

Age-Specific Considerations

Pediatric Patients

• Laboratory testing is generally not required for diagnosis in children, as ultrasound provides definitive diagnosis 1
• Labs may be indicated if complications are suspected or if the child appears systemically ill 5

Adult Patients

• Age and presence of anemia are significant predictive factors for malignancy on univariate analysis 4
• Colonic intussusception (P=0.004) and anemia (P=0.001) are independent predictors of malignancy on multivariate analysis, warranting more aggressive surgical approach 4
• Adult intussusception has a pathologic lead point in 90% of cases, with 54.5% having a tumor (27.3% malignant) 4, 3

Common Pitfalls to Avoid

• Do not delay imaging to obtain laboratory results in stable patients with suspected intussusception, as imaging is diagnostic 1
• Do not rely on laboratory tests alone for diagnosis, as adult intussusception presents with nonspecific symptoms (abdominal pain, nausea, vomiting) that cannot be differentiated by labs 6
• Do not order routine preoperative labs in uncomplicated pediatric cases where ultrasound confirms the diagnosis and the child is otherwise well 5
• Always check for anemia in adult patients, as this finding combined with colonic location significantly increases malignancy risk and influences surgical approach (en bloc resection without reduction) 4