White blood cells in the urine are typically the result of a urinary tract infection, according to MedicineNet.com. Urinary tract infections are usually located in the bladder or kidneys, although infections also occur in the ureters or urethra.
The presence of white blood cells in a urine sample is an abnormality usually indicative of a urinary tract infection because urine is generally considered a sterile fluid, asserts MedicineNet.com. Infections become increasingly serious the farther up into the urinary tract they are located. UTIs affect adults more frequently than children, and women more frequently than men. UTIs are considered more serious in children than in adults.
Pyelonephritis is an infection ensconced in the kidneys causing potentially serious symptoms such as fever, chills, nausea and vomiting, states MedicineNet.com. Cystitis, an infection of the bladder, is usually caused by Escherichia coli, a bacteria normally found in the gastrointestinal tract, according to Mayo Clinic. Women are prone to develop cystitis and urethritis (infection of the urethra) more frequently than men because of the shorter distance from the urethra to the anus in the female anatomy. Urine samples can sometimes be contaminated by white blood cells issuing from the opening of the vagina, according to MedicineNet.com