Vibrant does not recommend a “gluten challenge” to a patient who is already aware they have adverse symptoms driven by gluten. However, with any antibody testing, if the antigen (gluten, wheat) has been removed for a significant amount of time (variable amongst individuals), the body may no longer mount an IgA/IgG antibody response. To learn more about the lifespan of IgA and IgG antibodies, please view the Food Immunoglobulins handout.
While Vibrant does not recommend a gluten challenge, if the ordering practitioner wishes to recommend a gluten challenge for their patient, the protocol for amount of gluten and duration of challenge is 14 day gluten challenge with >3g gluten (2 slices of wheat bread per day). For more information, see https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3525791/pdf/nihms-380622.pdf
