What Does It Mean When You Have White Blood Cells in Your Urine?

White blood cells travels throughout the body and detect the presence of bacteria, viruses and other intruders, according to the University of Rochester Medical Center. If a foreign invader is detected, white blood cells multiply and destroy foreign invaders and protect the body against illness.

Pyelonephritis is an infection of the kidneys causing potentially serious symptoms such as fever, chills, nausea and vomiting, states MedicineNet.com. Cystitis is an infection of the bladder usually caused by Escherichia coli, a bacteria normally found in the gastrointestinal tract, according to Mayo Clinic. Women are more likely than men to develop cystitis and urethritis (infection of the urethra) because of the shorter distance from the urethra to the anus in the female anatomy. White blood cells from the opening of the vagina or the urethra can contaminate a urine sample, as noted by MedicineNet.com.

If a physician suspects a urinary tract infection, he may order a leukocyte esterase urine test to detect the existence of white blood cells in urine, according to the MedlinePlus. Although a positive reading may indicate an infection, trichomoniasis and vaginal secretions may cause a false positive test result.

If white blood cells are present, a physician may request a urine culture to confirm an infection, according to the American Association for Clinical Chemistry. A urine culture detects the presence of bacteria. If the doctor finds disease-causing bacteria in the urine sample, susceptibility tests are performed to discover an antibiotic that treats the urinary tract infection. When a person has chronic urinary infections, a physician may also order tests to check for diabetes and altered kidney functioning.