ABSTRACT
Under normal circumstances, the urine is sterile as it is formed and collects in the bladder. In fact, as it is collected after voiding, urine has a relatively small number of organisms, these being those which get into the specimen from the external genitalia. The number of organisms in the voided normal specimen can be reduced somewhat further by collecting the specimen by either a "mid-stream" or "clean catch" procedure. Organisms may invade the urinary tract and grow in urine and, according to Lang and Levin, bacteriuria is a sign associated with the most common of all the infectious diseases, urinary tract infection. Bacteria in the urine as an abnormality associated with disease began to be appreciated about the time of Louis Pasteur in the middle of the 19th century. Good results are achieved if certain basic principles of laboratory practice are followed and consideration is given to certain factors.
