A test to identify the site of a urinary tract infection. On awakening, the patient empties the bladder by passing urine sequentially into three test tubes (glasses). The amount of cellular debris visible to the naked eye in the glasses helps to determine whether the infection is located in the anterior urethra, posterior urethra, or prostate. If the first glass is turbid and the other two are clear, the anterior urethra is inflamed but the rest of the urinary tract is clear. If the initial specimen is clear and the second and third ones are turbid, the posterior urethra or prostate is inflamed. If only the third specimen is turbid, then only the prostate is inflamed.