5 year old has persistent normocytic anemia. High WBC, platelets, low RBC and hemoglobin. Normal MCV, MCH, ferritin and reticulocyte. What's the cause?

Need more tests,,, This is hard to determine as this is the case of a child. Other tests like a peripheral blood smear might help to find the cause. It would be best to see the doctor, preferably a pediatrician, for more tests and an exam. Best of luck.