What does a high number of pus cells in the urine indicate?

Q: I am a 27 years old man having a kidney stone of size 4 mm. My urine examination reports pus cell Occasional. What does it mean?

A:Presence of more than 5 pus cells per high power field in an unspun urine in male, and more than 10 pus cells in a female, is defined as pyuria. High number of pus cells in urine, or pyuria, usually indicates infection. There are conditions where infection may not be documented despite pyuria, and is then called sterile pyuria. Sterile pyuria may occur in presence of stones in the urinary tract and chronic infection like tuberculosis of urinary tract, apart from many other causes. Urine test does not show stones, and it may have been picked up on your ultrasound examination of the urinary tract. Ultrasound is a good screening investigation but has low specificity and sensitivity. Further investigations like x-ray or computerised tomography may be required to confirm and characterise the stone further, before any definitive therapy planning.