“…However, the utility of food-specific IgG testing specifically in FAPDs awaits further evaluation, and, although not proven, there is data suggesting a potential for clinical utility. Multiple studies have reported increased food-specific IgG or IgG4 in adults with FAPD, particularly IBS [ 43 , 74 , 101 , 103 , 104 ]. Multiple studies have also reported clinical improvement on elimination diets guided by IgG or IgG4 testing [ 104 , 105 , 106 , 107 , 108 , 109 ].…”