Food allergy is a growing problem, with an estimated 8% of children affected. Among food allergies, peanut allergy is particularly associated with severe allergic reactions. Despite the prevalence and risk of peanut allergy, there are limited therapeutic options, in part due to incomplete immunologic understanding of food allergy. Immunoglobulin A (IgA) is the most prevalent antibody in the gut, and it regulates commensal flora balance, neutralizes toxins, and opsonizes pathogenic microbes. It has been presumed that IgA may also be able to neutralize food antigens and prevent development of allergy, but that has yet to be shown. To address the question of whether peanut-specific IgA can prevent the development of allergy, we have developed and validated a clinical assay that can detect peanut-specific IgA in human stool. This ELISA-based assay is precise, with results replicable from the same sample over multiple tests. The assay is also specific to peanut IgA. We have also found that results are closely clustered when using multiple samples from the same person over time, indicating that production is consistent over time. Using this assay, we have found that there is a range of peanut-specific IgA levels in healthy, non-allergic people. The peanut-specific IgA levels do not correlate with total IgA levels in the stool. We aim to use this assay to examine the stools of peanut-allergic individuals to determine whether stool peanut-specific IgA is correlated with protection against peanut allergy.