A bladder biopsy is performed if abnormalities of the bladder are found, or if a tumor is grossly visible. During the biopsy a small portion of tissue is removed and sent to the laboratory for analysis. Update Date: 05/22/2008Scott M. Gilbert, MD, Department of Urology, Columbia-Presbyterian Medical Center, New York, NY. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.