My son is 7 yrs old.his iron was 20.9,mcv74.9 and platelets were 396..after 3 months of iron med, iron is 48, mcv 75,hct/pcv33.7 and plateles 420. ?

Still needs iron: MCV less than 80 indicates he still has anemia and it is a microcytic (small red blood cell size) anemia usually associated with iron deficiency. Serum iron is also low, should be greater than 50. Normal HCT is between 35-45%. It is important to have his doctor follow his labs closely to assure he is responding to iron and does not have another cause for anemia.

Fe: Fe deficiency does affect the MCV , the number of RBC's , the hemoglobin level, but not to my knowledge the platelets count. I would continue for one more month the iron treatment and check with your pediatrician.