Comparison of the delta neutrophil index with procalcitonin and C-reactive protein in sepsis

The purpose of this study was to compare the diagnostic performance of the delta neutrophil index (DNI) with procalcitonin and C-reactive protein (CRP) for the prediction of sepsis and its outcome.

A total of 128 consecutive patients who were tested by blood culture were enrolled. The DNI, procalcitonin, and CRP were measured, the blood was cultured, and other clinical data were obtained by retrospective chart review.

The DNI, procalcitonin and CRP increased with increasing disease severity (p < 0.05). The DNI (area under the curve (AUC) 0.932 for sepsis, 0.800 for survival) and procalcitonin (AUC 0.918 for sepsis, 0.831 for survival) had high diagnostic performance for the prediction of sepsis and survival. CRP also has good diagnostic power in predicting sepsis and survival (AUC 0.819 for sepsis, 0.723 for survival). The combination of the DNI and procalcitonin had higher AUC (0.964) than each of the biomakers for the prediction of sepsis. The cutoffs for the DNI, procalcitonin, CRP, and 'procalcitonin + DNI' for the diagnosis of sepsis were 12.3%, > 1.44 ng/mL, > 6.84 mg/L, and > 19.24, respectively. At least one of the DNI or procalcitonin values was high (> cutoff levels) in all sepsis or septic shock patients.

The DNI can be obtained easily from automated hematological analysis and is cost effective. Furthermore, the DNI has a high diagnostic power for predicting sepsis and survival, similar to procalcitonin and better than CRP. The combination of DNI and procalcitonin may improve the ability to predict the severity of sepsis and survival.