What is Helicobacter pylori Antigen?
Helicobacter pylori is a spiral Gram-negative bacterium that colonises the gastric mucosa, persisting in the acidic environment beneath the mucus layer. Active infection sheds bacterial antigens continuously into the gastrointestinal lumen; these antigens are detectable in stool by enzyme immunoassay. The presence of faecal antigen correlates with active mucosal colonisation, distinguishing current infection from past exposure or inactive disease that might be reflected by serology alone.