Neutrophil left shift and white blood cell count as markers of bacterial infection

Clin Chim Acta. 2016 Jun 1;457:46-53. doi: 10.1016/j.cca.2016.03.017. Epub 2016 Mar 28.


Neutrophil left shift and white blood cell (WBC) count are routine laboratory tests used to assess neutrophil state, which depends on supply from the bone marrow and consumption in the tissues. If WBC count is constant, the presence of left shift indicates an increase of neutrophil consumption that is equal to an increase of production. A decrease in WBC count indicates that neutrophil consumption surpasses supply. During a bacterial infection, large numbers of neutrophils are consumed. Thus, from onset of infection to recovery, dynamic changes occur in WBC count and left shift data, reflecting the mild to serious condition of the bacterial infection. Although various stimuli in healthy and pathological conditions also cause left shift, a change as sudden and significant is only seen in bacterial infection. Left shift does not occur in the extremely early or late phases of infection; therefore, assessing data from a single time point is unsuitable for diagnosing a bacterial infection. We argue that time-series data of left shift and WBC count reflect real-time neutrophil consumption during the course of a bacterial infection, allowing more accurate evaluation of patient condition.

Keywords: Bacterial infection; Band neutrophil; Left shift; Metamyelocyte; Myelocyte; Neutrophil; Segmented neutrophil.

Publication types

  • Review

MeSH terms

  • Bacterial Infections / blood*
  • Biomarkers / blood*
  • Blood Cell Count*
  • Humans
  • Neutrophils / cytology*


  • Biomarkers