shift to the left AE 10056383 SZ, SS, YH WEB: http://medical-dictionary.thefreedictionary.com/shift Blood cell lab test abnormal AE showing an increase in the number of immature leukocytes in peripheral blood. (in hematology) a predominance of immature leukocytes noted in a differential white blood cell count. It is usually indicative of an infection or inflammation. The term derives from a graph of blood components in which immature cell frequencies appear on the left side of the graph. white blood cell profile abnormal AE