<P> Left shift or blood shift is an increase in the number of immature leukocytes in the peripheral blood, particularly neutrophil band cells . </P> <P> Less commonly, left shift may also refer to a similar phenomenon in severe anemia, when reticulocytes and immature erythrocyte precursors appear in the peripheral circulation . </P> <P> The standard definition of a left shift is an absolute band form count greater than 700 / microL . There are competing explanations for the origin of the phrase "left shift," including the left-most button arrangement of early cell sorting machines and a 1920s publication by Josef Arneth, containing a graph in which immature neutrophils, with fewer segments, shifted the median left . </P> <P> It is usually noted on microscopic examination of a blood smear . This systemic effect of inflammation is most often seen in the course of an active infection and during other severe illnesses such as hypoxia and shock . Döhle bodies may also be present in the neutrophil's cytoplasm in the setting of sepsis or severe inflammatory responses . </P>

What is a left shift on a cbc