Which test is used to diagnose Helicobacter pylori infection?

• A. Serum gastrin level
• B. Urea breath test
• C. Eosinophils
• D. Stool fecal fat

Answer: (B)

Detecting active H. pylori relies on detecting the bacteria’s urease activity. The urea breath test works by giving the patient urea labeled with carbon. If H. pylori is present, its urease splits the urea into ammonia and carbon dioxide, and the labeled CO2 is exhaled in the breath and measured. This noninvasive test accurately confirms active infection and is also used after treatment to verify eradication. Serum gastrin level isn’t a diagnostic for H. pylori, as it reflects acid-related processes rather than infection. Eosinophils indicate allergy or parasitic processes, not H. pylori, and stool fecal fat assesses fat absorption, not infection.