Yeast (Saccharomyces spp.) IgG4 details

This test measures IgG4 antibodies to Saccharomyces yeast, the type used to make bread, beer and wine and found in many fermented foods. IgG4 food tests are sometimes ordered to look at possible food sensitivities that are not immediate allergies. A higher result generally reflects exposure — your immune system has met yeast through your diet — and IgG4 is often associated with tolerance rather than an allergic reaction. A low result usually means little recent exposure. The link between food IgG4 levels and symptoms is debated, and this result does not diagnose a yeast allergy, which is assessed with IgE testing.