The predicting value of neutrophil VCS parameters in the diagnosis of bacterial infection

Abstract

Objective To investigate the clinical value of mean channel of neutrophil volume (MNV), mean channel of neutrophil conductivity (MNC) and mean channel of neutrophil scatter (MNS) in predicting acute bacterial infection.Methods Peripheral blood samples from 112 patients with positive blood cultures for bacteria,70 healthy subjects and 45 non-infectious subjects with high white blood cell count(WBC) were studied using the Coulter LH 750 hematology analyzer.MNV, MNC, MNS and neutrophil volume distribution width (NDW) were retrospectively analyzed and compared with total WBC, percentage of neutrophils,neutrophil left-shift and CRP.112 blood bacterial infections were grouped according to WBC count (A:WBC ＜11.0×109 /L;B:11.0×109/L≤WBC＜15.0×109 /L;C:WBC≥15.0×109 /L) and neutrophil rate (NE ＜ 0.85 and NE ≥ 0.85 ).Results MNV and NDW increased significantly in septic patients (154.17 ± 10.08,24.36 ± 4.14 ) compared with those of healthy control group (142.09 ± 4.13,19.04 ± 1.97) and non-infectious patients with high WBC group ( 150.63 ± 8.14,20.19 ± 4.73 ).There was statistically significant difference (F value were 20.738 and 28.190 respectively,P ＜ 0.01 ). On the contrary, MNS decreased significantly in septic patients (137.15 ± 7.61 ) compared with that of healthy group (144.51±4.36) and nonspetic patients with high WBC group (142.45±7.11) ,there was significant statistical difference (F=5.217,P＜0.01).The MNV, NDW and MNS of A group were 148.09±5.76,22.39±1.97,140.07±6.11 respectively.The MNV, NDW and MNS of B group were 152.83±5.75,24.14±1.35,141.44±5.35 respectively.The MNV, NDW and MNS of C group were 164.28±6.49,29.42±5.93,134.27±9.61 respectively. There was statistically significant difference compared with healthy group (F value were 24.720,31.642,7.931, P ＜ 0.01).The MNV, NDW and MNS in the group with NE ＜0.85 were 149.17±9.06,22.59±2.73,141.19±4.34 respectively.The MNV, NDW and MNS in the group with NE≥0.85 group were 159.03±10.23,27.64±4.51,135.62 ± 8.95 respectively.There was statistically significant difference compared with healthy group ( F value was 23.970,51.309,19.792,P＜0.01).With a cut-off of 150 for the MNV, a specificity of 90% and sensitivity of 70% were achieved.NDW was associated with neutrophil left-shift (r=0.33,P＜0.01).With a cut-off of 23 for the NDW, a specificity of 100% and a sensitivity of 72% were achieved.The sensitivity of the MNV and NDW was better than total white blood cells count (with a cut-off≥ 11.0×109 /L, the sensitivity was 57% ), percentage of neutrophils( with a cut-off≥0.85, the sensitivity was 44% ) and neutrophil shift to left ( with a cut-off ＞5%, the sensitivity was 66% ) and CRP (with a cut-off ≥10 mg/L, the sensitivity was 65% ).Conclusions The MNV and NDW of the neutrophil can reflect the morphologic change of neutrophil sensitively and specificialy in acute infection. As quantitative, objective and more sensitive parameters, MNV and NDW may have a potential role for predicting the acute bacterial infection. Key words: Bacterial infections; Neutrophils; Blood cell count