Why do urostomates occasionally notice blue discoloration in the urostomy pouch or overnight drainage bag? Be assured there is nothing wrong with the appliance. In recent laboratory tests conducted by ConvaTec, the blue color was found to be the result of normal bacterial decomposition of an essential amino acid called tryptophan.
There is no clinical evidence, according to an article in the American Journal of Nursing, to indicate that the production of indigo blue is harmful or that the dietary tryptophan should be limited. If you are concerned, please talk with your doctor. Tryptophan is part of the regular intake of dietary protein. As it passes through your system, it undergoes a series of chemical changes that ultimately result in a blue color when it finally oxidizes in the urostomy pouch.