Thanks for your query. Microcytosis means his red blood cells are a bit smaller in size than usual & the common causes are iron deficiency & thalassemia trait ( both are common non-serious conditions) Mild leukocytosis means the white cells ( White blood cells, or leukocytes are cells of the immune system involved in defending the body against both infectious disease and foreign materials) are increased in number . lymphocyte is a type of white cell. Lymphocytosis (increased lymphocyte count) & activated lymphocytes are commonly seen in viral infectios in children. Hemoglobin electrophoresis will confirm the thalessemia trait if that is there. There are no reasons to worry and should wait for electrophoresis report. Hope you find the explaination useful.