Shift to the left


I understand that in a shift to the left we have immature WBC but why it is called "shift to the left"?



2 Posts

Imagine a family standing in a line by age. The toddler to the far left. To the right of them is the preschooler, then school aged child, teenager, and finally adult. This is the same sort of "line" wbc are in. When you shift to the left, you are shifting from the adult "mature" wbc. To the "immature" ones. Remember that only the mature wbc are effective in fighting infection. Hope that helps!

Specializes in NICU, ICU, PICU, Academia. Has 46 years experience.

Actually, the term 'left shift' derives from the days when blood was looked at under a microscope to do the cell counts. There were columns in which the lab tech or physician (all residents used to learn to do this) recorded by tally marks the number of each type of cell counted in a grid superimposed over a blood smear. The less mature cells were in the farthest left columns. Thus, a 'left shift' when you viewed the completed count. True story- ask an older physician! (or nurse)


259 Posts

It makes sense. Thank you!!


55 Posts

Specializes in ICU, PROGRESSIVE CARE. Has 5 years experience.

Thanks, always wondered that too.

allnurses Guide


3 Articles; 5,581 Posts

Specializes in Adult Internal Medicine. Has 12 years experience.

Labs reports always list a dif in order: bands, neuts, eos, baso, lymphs, monos that sum to 100.

An increase in bands is a literal shift of that % to the left of the paper.