cagA is an H. pylori gene associated with the CagA protein, which can alter signaling in stomach cells. CagA-positive strains are important in research on H. pylori disease, but detecting the gene in stool is not the same as seeing cell injury or diagnosing cancer.
On this page
How CagA works in research
H. pylori can deliver CagA into host cells using a type IV secretion system. The virB and virD labels relate to parts of bacterial secretion machinery. Experimental work explains this mechanism; a stool gene test does not directly measure delivery of CagA into your stomach cells. [1]
What GI-MAP cagA-positive means
cagA is one of the manufacturer’s selected virulence targets. A detected result identifies that genetic target under the assay’s reporting conditions. It does not report every cagA variant, protein activity or the condition of the stomach lining. [2]
What to do with cancer concerns
Do not convert cagA-positive into a personal cancer probability. Nor should a negative cagA result be used to dismiss confirmed H. pylori infection. Decisions about infection, treatment and any further stomach evaluation depend on clinical history and appropriate testing, not one gene flag.
The existing H. pylori guide provides the broader clinical context. Keep this page for the narrower question of what the cagA result actually measures.
Common questions
Is CagA positivity a diagnosis of an ulcer?
No. The gene result does not visualize an ulcer or establish its presence. Symptoms and, when appropriate, further examination determine that.
Does cagA tell me which antibiotic to take?
No. It is a virulence marker, not a susceptibility result. Treatment selection and confirmation of eradication belong in a clinician-directed plan. [3]
Sources and review
Sources checked October 7, 2026. Manufacturer material describes the test; clinical guidance and research support the interpretation limits.
- Backert et al.: CagA translocation through type IV secretion, 2000
- Diagnostic Solutions Laboratory: GI-MAP interpretive guide (manufacturer specifications)
- American College of Gastroenterology: 2024 H. pylori guideline summary
Medical review of this article is pending. For a correction or source question, contact GI MAP Test.