CBC counts will be affected by underlying disease and its severity or treatment response as well as comorbidities. Conception of question, however, from clinical standpoint is less relevant.
As far as I know, hemoglobin and hematocrit reach its final result after 30 minutes from the end of any blood red cells pack transfusion. I believe white blood cells and platelets are not modyfied in quantity with this kind of transfusion.
As Ricardo is saying, Hb and red cells counts reach a final value about 30-60 minutes, and then it depends on the clinical situation of the patient. As for platelets and white blood cells, there are no changes in final values.