The value of delta neutrophil index in neonatal sepsis diagnosis, follow-up and mortality prediction.

Background: The complete blood cell count (CBC) and peripheral blood smear were the most commonly ordered tests for the diagnosis of neonatal sepsis. Delta neutrophil index (DNI) shows leucocyte differentiation and calculated while CBC is performed.

Aims: We aimed to evaluate the value of DNI in neonatal sepsis.

Study Design: DNI was measured with Siemens Advia 2120 and 2120i devices. DNI was calculated as (neutrophil and eosinophil count in myeloperoxidase channel)-(polymorphonuclear leucocyte count in nuclear lobularity channel).

Results: Study population included 141 and 87 neonates in sepsis (110 proven, 31 clinical) and control groups. Demographic characters were similar between groups. Proven sepsis group had lower birthweight and higher late-onset sepsis rate than clinical sepsis and control groups. Median DNI (16.3 vs 1,4) and CRP (6.8 vs 0,03 mg/dl) were significantly higher in sepsis group. Proven sepsis group had significantly higher DNI level than clinical sepsis group (20.8 vs 9.1). Cut-off level of DNI was 4.6 with 85% sensitivity and 80% specificity. Cut-off level of CRP was 0.58 mg/dl with 81% sensitivity and 82% specificity. Combination of DNI and CRP gave 98% sensitivity and 76% specificity. Mortality rate in sepsis group was 39%. Median DNI level in patients with mortality was significantly higher (30.1 vs 9.6). Cut-off level of DNI for mortality prediction was 16.1 with 75% sensitivity and 65% specificity. Follow-up levels of DNI was significantly decreased in 6-10 days to normal levels (16.3 to 4.2).

Conclusions: DNI was found to be useful in the diagnose, follow-up and mortality prediction of neonatal sepsis without extra blood to CBC.