Concomitant Prevalence of Low Serum Diamine Oxidase Activity and Carbohydrate Malabsorption

) breath tests. Additionally, serum diamine oxidase (DAO) measurements were performed. Individuals with low serum DAO activity (<10 U/mL), GI symptoms, and response to histamine-free diet were diagnosed with HI. Of all 439 patients, 341 (77.7%) were found with 7 various GI conditions. In total, 94 (21.4%), 31 (7.1%), and 100 (22.8%) individuals presented LM, FM, or HI only, whereas 116 (26.4%) patients showed an overlap of GI entities investigated here. Interestingly, 89 out of 241 (36.9%) individuals with carbohydrate malabsorption were also diagnosed with HI (LM + HI: 52 [11.8%], FM + HI: 23 [5.2%], and LM + FM + HI 14 [3.2%] individuals). In conclusion different combinations of LM, FM, and HI are present in individuals with unclear abdominal discomfort/pain. In clinical practice we suggest testing for LM, FM, and additional HI in the diagnostic work-up of these patients. Depending on these various diagnoses possible, patients should get an individualized dietary advice.