What is meant by “shift to left” of neutrophils

Have you ever heard “shift to left” in diagnostic criteria of some disease (e.g appendicits – mantrels scoring system). Let’s discuss what’s exactly meant by this term, shift to left.

What is meant by left shift neutrophils

First of all we need to have a brief background. Less mature neutrophils are called bands or stabs (due to their appearance).

In acute bacterial infection, there will be increase in total number of mature neutrophils along with less mature bands or stabs in response to the infection.

In old days, when the laboratory reports were written by hand, less mature neutrophils were written first on the left side of the lab report. This term is holdover from that era and increase in less mature neutrophils is still called as “shift to left” in acute infections, signifying the left shift wbc count or to be specific left shift neutrophils.

Less mature neutrophils are less than 10% of the total neutrophils in the blood stream. So if the complete blood picture says that there is a shift to left then it means that the less mature neutrophils are more than 10% in this patients blood.