We thank Sood et al for their interest in our recent large scale validation of plasma anti-CdtB and antivinculin as biomarkers for the diagnosis of irritable bowel syndrome (IBS) with diarrhea. The authors point out strengths and limitations of our study and the development of biomarkers in IBS. We appreciate their very objective view of biomarkers in general and suggestions for the practical needs for the future. They point out the importance of a positive identity biomarker for IBS.