Hello Doctor, my 11.5 year old sons doctor called me back yesterday with blood work results she said everything came back negative just they fount red blood cells in his urine 20-50 count.She said bring him Monday so they can retest, she asked does lupus or sickle cell run in families i said, no. She said it may not be anything shes seen test with red blood cells in urine and turned out nothing. I know it could be gall or kidney stones, extensive activities,hes in bball,plays a lot.Hes been having childhood migraines for years taking meds for that hell rest and fall right to sleep at times. Hes been saying his knees been hurting coach said maybe growth spurt but my son thinks its from when he hurt it on wall months ago. Im sorry im now stressed this weekend hearing that i cant function at all please help.