The complete blood count to diagnose septic shock.

The complete blood count has a longstanding role in the diagnosis of septic shock. Despite its limitations, this is a pragmatic tool because patients will generally have a blood count measured upon presentation to the hospital. Therefore, it is sensible to extract as much information from these values as possible. Although the white blood cell count continues to attract the most attention, it is the least useful. Emerging evidence suggests that emphasis should be shifted to the neutrophil to lymphocyte ratio (NLR) and perhaps the fraction of immune granulocytes.