Pyuria is the presence of pyospheres (white blood cells) in the urine (<3-4). It is possible that macroscopically there is no change in the colour of urine and pyuria is diagnosed with the general urine test (urinalysis). However, when there are too many pyospheres, there is macroscopic blurring of the urine. There are numerous causes involved in Pyuria, but the most common one is infections. Other causes may be urolithiasis, foreign bodies (e.g. bladder catheters) or specific infections (e.g. tuberculosis).