5mm to cause you severe pain, but with no blood found in your urine
AND a negative cat scan, your pain might not be caused by a
kidney stone. Why not wait a short time and have both re-done to see if anything shows up the second time in either test. If not you'll know and can go from there looking at other possibilities for your pain. If positive on either test, then you'll know that way too, for sure. Good Luck and please let us know what you find out.