The most common sign of bladder cancer is microscopic hematuria, a finding often detected by a primary care physician. It is important to reiterate that microhematuria is hardly a diagnosis of bladder cancer, as most cases simply reflect a benign cause. Nevertheless, if this is detected, it is important to undergo a thorough evaluation for its potential cause. In general, the definitive test to detect a bladder tumor is a cystoscopic or direct examination of the bladder mucosa by an experienced urologist. In some cases an overt tumor can be visualized, while in others such as carcinoma in situ(see below), merely subtle changes in the mucosa are observed and subsequently biopsied. A biopsy involves removing a small piece of the abnormally appearing tissue, which is ususally taken from the bladder through a cystoscope and sent to a pathologist for microscopic evaluation. The diagnosis of bladder cancer can only be made upon examining the cells under a microscope. As will be discussed, it is the nature and appearance of these cells that will determine precisely the type of bladder tumor-in most cases a transitional cell type-as well as the likelihood that it will invade other tissue layers readily, known as tumor grade.

Once the diagnosis has been made, it is important to discern the extent of its growth within the bladder wall and potentially to adjacent organs. This process is known as staging. In addition, other screening tests will be necessary to evaluate distant organs for the presence of metastases. As will be discussed, this "staging" evaluation will aid in directing the appropriate treatment.