What diagnostic tests are performed for a patient with suspected gastric ulcer?

Diagnostic Testing for Suspected Gastric Ulcer

Upper endoscopy with biopsy is the reference standard and primary diagnostic test for suspected gastric ulcer, with biopsies mandatory from the base and edges of all gastric ulcers regardless of their benign appearance. 1, 2

Primary Diagnostic Approach: Upper Endoscopy with Biopsy

All gastric ulcers require endoscopic biopsy because visual inspection alone has significant false-negative rates for malignancy. 2, 3 The 2024 AGA guidelines specify the following biopsy protocol:

• Biopsy specimens should be taken from both the base and edges of the ulcer 1
• A minimum of 6 biopsies from areas of gastric mucosal abnormality achieves adequate diagnostic accuracy 2
• Biopsy may be individualized only in very low-risk scenarios (young non-Hispanic white patient taking NSAIDs with shallow, flat ulcer and associated erosions), though this remains controversial 1

Critical Pitfall to Avoid

Endoscopy correctly diagnoses only 65% of malignant gastric ulcers by visual appearance alone—the combination of endoscopy, biopsy, and cytology increases diagnostic accuracy to 95%. 4 Even benign-appearing ulcers can harbor malignancy, particularly in healing or healed chronic ulcers where malignant transformation may occur at the ulcer base. 5

Helicobacter pylori Testing

All patients with suspected or confirmed gastric ulcer must undergo H. pylori testing to identify the underlying cause and guide curative treatment. 6, 7

H. pylori Testing Protocol

During endoscopy, obtain 5 biopsy specimens for H. pylori detection from the following locations: 1

• Greater and lesser curve of gastric body
• Incisura angularis
• Greater and lesser curve of antrum
• Place specimens in 2 separately labeled jars (body; antrum/incisura) 1

Gastric body biopsies are especially critical in patients using proton pump inhibitors because H. pylori migrates proximally from antrum to body during acid suppression. 1

Non-Invasive H. pylori Testing Options

For non-endoscopic evaluation:

• Urea breath test: sensitivity 88-95%, specificity 95-100% 6
• Stool antigen test: sensitivity 94%, specificity 92% 6
• Stop PPIs, antibiotics, and bismuth for at least 2 weeks before testing to avoid false-negative results 6
• Do not rely on serology alone—it cannot confirm active infection 6

Imaging Studies

For Uncomplicated Suspected Gastric Ulcer

No imaging is indicated for uncomplicated suspected gastric ulcer—proceed directly to upper endoscopy. 2

For Suspected Perforated Gastric Ulcer

CT abdomen and pelvis with IV contrast is the first-line imaging modality for suspected perforation (Strong recommendation, 1C). 2, 7

CT technical specifications:

• Use IV contrast to assess nodular wall thickening and soft tissue attenuation 1, 2
• Use neutral oral contrast (water or dilute barium) to delineate the intraluminal space 1, 2

CT findings of perforation include: 2, 7

• Extraluminal gas/pneumoperitoneum
• Focal wall defect or ulcer
• Wall thickening
• Mesenteric fat stranding
• Unexplained intraperitoneal fluid or ascites

Chest/abdominal X-ray should only be performed when CT is not promptly available (Strong recommendation, 1C), though free air is detected in only 30-85% of perforations, making it less reliable than CT. 2, 7

Upper GI Series (Fluoroscopy)

Double-contrast upper GI series is beneficial when endoscopy is unavailable or contraindicated for evaluating structural and functional abnormalities of the stomach. 1

Fluoroscopy has special value for scirrhous (linitis plastica) gastric carcinoma, which may be missed on endoscopy due to poor biopsy sensitivity in this subtype. 2 Malignant ulcers on fluoroscopy show nodularity of adjacent mucosa, mass effect, or coarse, lobulated, irregular radiating folds. 1

Laboratory Studies

For suspected complicated gastric ulcer (perforation or bleeding), obtain: 6, 7

• Complete blood count
• Metabolic panel
• Arterial blood gas analysis

These tests assess disease severity and guide resuscitation but do not confirm gastric ulcer diagnosis. 6 Leukocytosis, metabolic acidosis, and elevated serum amylase are commonly associated with perforation but are non-specific. 7

Clinical Algorithm Summary

Uncomplicated Suspected Gastric Ulcer:

1. Upper endoscopy with minimum 6 biopsies from base and edges of ulcer 1, 2
2. Obtain 5 additional biopsies for H. pylori (body, incisura, antrum in 2 jars) 1
3. No imaging indicated 2

Suspected Perforated Gastric Ulcer:

1. Obtain routine labs and arterial blood gas immediately 6, 7
2. CT abdomen/pelvis with IV contrast and neutral oral contrast 2, 7
3. Chest/abdominal X-ray only if CT unavailable 7

H. pylori Testing (Non-Endoscopic):

1. Stop PPIs, antibiotics, bismuth for ≥2 weeks 6
2. Urea breath test or stool antigen test 6
3. Avoid serology for treatment decisions 6