Evaluation of automated hematologic VCS parameters in severe sepsis and septic shock: a case-control study

Introduction

A cheap and quick hematologic diagnostic parameter for detection of sepsis would have both economic and therapeutic benefits. The Coulter LH series hematology analyzer uses the VCS technology (Volume, Conductivity, Laser Scatter) providing information about cell volume, size, internal structure, and surface morphology. Many authors analyzed the clinical usefulness of VCS parameters in reactive neutrophils for detection of sepsis. An increase in mean cell volume and a decrease in mean light scatter in septic patients have been described. Our aim is to verify the correlation between VCS parameters and sepsis.

Methods

We enrolled 92 patients admitted in our ICU and divided them into two groups: Controls (48) and Sepsis (44). We collected blood samples immediately after making the diagnosis. All samples were analyzed by Coulter LH 500 hematology analyzer. We realized ROC curves for each V, C, S parameter.

Results

The AUC was 0.816 (95% CI, 0.722 to 0.889) for mean-V value; 0.546 (95% CI, 0.439 to 0.650) for mean-C value; 0.604 (95% CI, 0.497 to 0.704) for mean S value (Figure 1). The correlation with sepsis was a linear positive one for mean-V (strong) and mean-C (weak) instead of a linear negative one for mean-S. The best cut-off value for mean-V was >163 (Sens: 84.09%; Spec: 68.75%); >137 for mean-C (Sens: 72.73%; Spec: 41.67%); <134 for mean-S (Sens: 56.82%; Spec: 64.58%).

Figure 1

Conclusions

Our study shows the high diagnostic performance of mean-V and the weak one of mean-C and mean-S in septic patients. The clinical usefulness of mean-V is strengthened by the quickness and cheapness of its analysis. It could be tested daily or more as a valid laboratorial help for critical patient's clinical assessment.