What are the diagnostic tests for Peptic Ulcer Disease (PUD)?

Diagnostic Tests for Peptic Ulcer Disease

Primary Diagnostic Approach

For uncomplicated PUD, upper endoscopy with biopsy is the gold standard diagnostic test, combined with H. pylori testing in all patients. 1, 2, 3

Endoscopy with Histopathology

• Upper endoscopy with histopathological examination is the definitive diagnostic test for PUD, allowing direct visualization of ulcers and tissue sampling to rule out malignancy. 3
• Endoscopy should be performed in patients over 55 years or those with alarm symptoms (bleeding, weight loss, dysphagia, anemia) to exclude gastric cancer and other serious pathology. 3
• Histopathological examination can use H&E stain or special stains (Giemsa, Warthin-Starry), with special stains being more accurate for detecting H. pylori. 4

H. pylori Testing (Mandatory in All PUD Patients)

All patients with suspected or confirmed PUD must undergo H. pylori testing, as this identifies the underlying cause and guides curative treatment. 5, 1, 2

Non-Invasive Tests (Preferred for Initial Diagnosis)

• Urea breath test (13C or 14C): Most accurate non-invasive test with sensitivity 88-95% and specificity 95-100%. 1, 4
• Stool antigen test: Sensitivity 94%, specificity 92% for active infection. 1, 4
• Serology: Less accurate (sensitivity 84%, specificity 90%) and cannot confirm active infection or cure—use only when other tests unavailable. 1, 4

Critical Testing Precautions

• Stop PPIs, antibiotics, and bismuth for at least 2 weeks before testing to avoid false-negative results—this is the most common pitfall. 1
• Urea breath test and stool antigen test can confirm eradication after treatment; serology cannot. 1, 3, 4

Invasive H. pylori Testing

• Endoscopic biopsy with histopathology, rapid urease test, or culture can be performed during endoscopy. 5, 4

Diagnostic Tests for Complicated PUD

For Suspected Perforated PUD

CT scan is the first-line imaging modality for suspected perforation (Strong recommendation, 1C). 5, 1, 2

Laboratory Studies

• Routine labs (CBC, metabolic panel) and arterial blood gas analysis are strongly recommended. 5, 1, 6
• Leukocytosis, metabolic acidosis, and elevated serum amylase are commonly associated with perforation but are non-specific. 5, 1, 6

Imaging Studies

• CT scan: Detects pneumoperitoneum, intraperitoneal fluid, bowel wall thickening, and extraluminal contrast—sensitivity superior to X-ray. 5, 2
• Chest/abdominal X-ray: Use only when CT unavailable; detects free air in 30-85% of perforations (erect or left lateral decubitus views). 5, 2
• Water-soluble contrast study: Administer orally or via NG tube when free air not seen on imaging but perforation still suspected (Weak recommendation, 2D). 5, 2

Important Caveat

• Up to 12% of perforations have normal CT scan—if clinical suspicion remains high, proceed with contrast studies or surgical exploration. 2

For Bleeding PUD

H. pylori testing is mandatory in all bleeding peptic ulcer patients (Strong recommendation, 1C). 5

Laboratory Studies

• CBC to assess anemia and hemodynamic status. 5
• Type and crossmatch for potential transfusion. 5

Endoscopy

• Urgent upper endoscopy for diagnosis and therapeutic intervention (hemostasis). 5
• Obtain tissue biopsy for H. pylori testing during endoscopy. 5

H. pylori Testing Timing

• Perform urea breath test or stool antigen test after acute bleeding controlled, as accuracy may be reduced during active bleeding. 5
• Eradication therapy reduces rebleeding rate from 26% to significantly lower rates. 5

Test-and-Treat Strategy

For patients under 55 years without alarm symptoms and low gastric cancer risk, non-invasive H. pylori testing followed by eradication therapy without endoscopy is appropriate. 3