Provided is a method of determining a risk of pouchitis development following a surgical procedure whereby colon is removed and an internal pouch is created in a patient with UC by determining a first pANCA titer, where the first pANCA titer is determined following the surgical procedure; determining a second pANCA titer at a later time; and comparing the first pANCA titer and the second pANCA titer, where a significantly elevated second pANCA titer indicates an increased risk of pouchitis development. Also provided is a method of determining a risk of pouchitis development following a surgical procedure whereby colon is removed and an internal pouch is created in a patient with UC by determining a first pANCA titer, where the first pANCA titer is determined prior to the surgical procedure; determining a second pANCA titer following said surgical procedure; and comparing the first pANCA titer and the second pANCA titer, where a significantly elevated second pANCA titer indicates an increased risk of pouchitis development.