What woukd cause my 7 year old daughter to always have white and red blood cells in her urine? Dr did labs to check kidneys. They seem fine

Poor collection. The best urine for study from a 7 yo girl is a free flowing, mid stream, sample collected as they spread their labia and pee like a male. Most squat/pee collected as a dribble can be a vaginal wash out and contain a wide collection of non bladder materials.