The complete blood count to diagnose septic shock

Abstract

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.

Keywords: Shock, septic; leukocytosis; lymphopenia; neutrophils; thrombocytopenia.

Figure 1

Suggested approach to interpretation of the NLR in evaluation of septic shock. Note, however, that values may vary depending on the clinical context and other sources of physiologic stress. The NLR reflects physiologic stress, rather than being a specific indicator of septic shock. NLR, neutrophil to lymphocyte ratio.