Leucocytes (white blood cells)
In urine, leucocytes are usually associated with a urinary infection but sometimes may indicate a more severe renal problem (Steggall, 2007). When white blood cells are present in the urine, patients are said to have pyuria (pus in the urine). To establish the cause, a clean-catch urine sample should be examined under a microscope, cultured to see what bacteria grows and tested for sensitivity to establish antibiotic treatment. Where no bacterial cells are detected, the patient is said to have sterile pyuria; this can occur in tuberculosis and inflammatory disease of the kidneys (Higgins, 2007).