Revisiting the white blood cell count: immature granulocytes count as a diagnostic marker to discriminate between SIRS and sepsis - a prospective, observational study

Axel Nierhaus,Dominic Wichmann,Stephan A Braune,Jo Linssen,Jörg Hedke,Stefan Kluge,Nina M Eismann,Stefanie Klatte

doi:10.1186/1471-2172-14-8

Abstract

BackgroundSepsis is a serious disease condition and a major cause of intensive care unit (ICU) admission. Its diagnosis in critically ill patients is complicated. To diagnose an infection rapidly, and to accurately differentiate systemic inflammatory response syndrome (SIRS) from sepsis, is challenging yet early diagnosis is vital for early induction of an appropriate therapy. The aim of this study was to evaluate whether the immature granulocyte (IG) count is a useful early diagnostic marker of sepsis compared to other markers. Therefore, a total of 70 consecutive surgical intensive care patients were assessed. IGs were measured from whole blood samples using an automated analyzer. C-reactive protein (CRP), lipopolysaccharide binding protein (LBP) and interleukin-6 (IL-6) concentrations were also determined. The observation period was a maximum of 21 days and ended with the patients’ discharge from ICU or death. Receiver operating characteristic (ROC) analyses were conducted and area under the curve (AUC) was calculated to determine sensitivities and specificities for the parameters.ResultsWe found that the IG count significantly discriminates between infected and non-infected patients (P < 0.0001) with a sensitivity of 89.2% and a specificity of 76.4%, particularly within the first 48 hours after SIRS onset. Regarding the discriminative power for infection, the IG count was more indicative than other clinical parameters such as CRP, LBP and IL-6, which had a sensitivity of less than 68%. Additionally, the highest diagnostic odds ratio (DOR) with 26.7 was calculated for the IG count within the first 48 hours. During the course of the disease ROC curve analyses showed a superior positive predictive value of the IG count compared to the other measured parameters during the first five days following the fulfillment of SIRS criteria. However, the number of IGs was not correlated with ICU mortality.ConclusionsThe total number of IG in peripheral blood from ICU patients is a good marker to discriminate infected and non-infected patients very early during SIRS. However, the IG count is not suitable as a prognostic marker for mortality. Routine and serial measurement of IGs may provide new possibilities for rapid screening of SIRS patients on ICU with suspected infections.

Highlights

Sepsis is a serious disease condition and a major cause of intensive care unit (ICU) admission
We demonstrated that the immature granulocyte (IG) count had greater sensitivity and specificity (89.2% and 76.4% respectively) than other parameters (CRP, lipopolysaccharide binding protein (LBP) and IL-6) which all had sensitivities of less than 68%
Our findings demonstrate that sepsis is associated with an increased immature granulocyte count

Summary

Introduction

Sepsis is a serious disease condition and a major cause of intensive care unit (ICU) admission. According to the ACCP/SCCM consensus conference both SIRS and sepsis are characterized by the occurrence of at least two of the following conditions: (1) body temperature >38°C or 90 beats per minute; (3) respiratory rate >20 breaths per minute or PaCO2 12,000/cu mm, 10% immature (band) forms. In addition to these criteria, the term sepsis is defined as an inflammatory systemic response arising from an infection [1]. Microbiological blood cultures are used to identify pathogens but, in addition to their low specificity, they are a poor early marker because of the time needed to obtain results [6,7]

Objectives

Methods

Results

Discussion

Conclusion