Gastritis and IgA Elevation

Diagnostic Considerations

The American Gastroenterological Association recommends testing for H. pylori infection using non-invasive methods when elevated IgA is found in the context of dyspeptic symptoms 6
The American Gastroenterological Association suggests confirming gastritis diagnosis with endoscopy and histopathology using the updated Sydney protocol (5 topographically separated biopsies) 1, 2, 3
The American Gastroenterological Association advises that if H. pylori is detected, eradicate the infection and confirm successful eradication with subsequent non-serologic testing 1, 2, 3
The American College of Gastroenterology recommends that in patients with histology compatible with autoimmune gastritis, check parietal cell antibodies and intrinsic factor antibodies rather than relying on IgA levels 1, 2, 4

Elevated IgA can occur in other conditions beyond gastritis, so the finding must be interpreted in clinical context with endoscopic and histologic confirmation 1, 2
Parietal cell antibodies can be falsely elevated in H. pylori infection and other autoimmune diseases, so IgA elevation alone does not distinguish between autoimmune and H. pylori-associated gastritis 1, 2

In autoimmune gastritis, the primary serologic markers are parietal cell antibodies and intrinsic factor antibodies, not IgA elevation 1, 2, 3, 4
H. pylori-associated gastritis is the most common form of atrophic gastritis and the primary driver of IgA elevation in gastritis patients 5, 6