Blood In Urine

Patient: I’m a 38 yr old female. Had a full physical a month ago and blood was found in my urine. Re-tested 3 times, always had moderate traces of blood. Doctor did a ultrasound on my bladder and kidneys test came back fine no kidney stones, etc.,. What could this be and what is the next step? Is moderate traces of blood normal or do I seek further testing? IF so what is next?Thank you!