Combining immature and total neutrophil counts to predict early onset sepsis in term and late preterm newborns: use of the I/T2.
Combining immature and total neutrophil counts to predict early onset sepsis in term and late preterm newborns: use of the I/T2.
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DOI：
10.1097/inf.0000000000000297
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发表时间：
2014-08
期刊：
影响因子：
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通讯作者：
Escobar GJ
中科院分区：
文献类型：
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作者：
Newman TB;Draper D;Puopolo KM;Wi S;Escobar GJ
中性粒细胞绝对计数和未成熟/总中性粒细胞比率（I/T）提供了有关新生儿早发性脓毒症风险的信息。但是，目前还不清楚如何将它们潜在重叠的信息联合收割机组合成一个单一的似然比。我们获得了在北方加州和布里格姆妇女医院出生的66，846名婴儿的血培养和全血细胞计数的电子记录，并在间隔<1小时的情况下进行人工分类。我们假设未成熟中性粒细胞计数（I）除以总中性粒细胞计数（T）的平方（=I/T2）将提供感染风险的有用总结。我们使用受试者工作特征曲线下面积（c）评价了I/T2区分致病菌血症新生儿与其他新生儿的能力。I/T2（c=0.79; 95% CI：0.76，0.82）的区分度与Logistic模型的区分度相似，该模型具有中性粒细胞绝对计数和未成熟中性粒细胞比例（c =0.80，95% CI：0.77，0.83）的24种组合中的每一种组合的指示变量。I/T2的辨别力随着年龄的增长而提高，从<1小时的0.70提高到≥4小时的0.87。然而，60%的I/T2的似然比为0.44至1.3，因此仅最小程度地改变了疾病的预测试几率。计算I/T2可以增强对早发性脓毒症的预测，但CBC主要在>4小时龄时进行，并且当感染的预测试概率接近治疗阈值时仍然有帮助。
The absolute neutrophil count and the immature/total neutrophil ratio (I/T) provide information about the risk of early-onset sepsis in newborns. However, it is not clear how to combine their potentially overlapping information into a single likelihood ratio. We obtained electronic records of blood cultures and of complete blood counts with manual differentials drawn <1 hour apart on 66,846 infants ≥34 weeks gestation and <72 hours old born at Kaiser Permanente Northern California and Brigham and Women’s Hospitals. We hypothesized that dividing the immature neutrophil count (I) by the total neutrophil count (T) squared (=I/T2) would provide a useful summary of the risk of infection. We evaluated the ability of the I/T2 to discriminate newborns with pathogenic bacteremia from other newborns tested using the area under the receiver operating characteristic curve (c). Discrimination of the I/T2 (c=0.79; 95% CI: 0.76, 0.82) was similar to that of logistic models with indicator variables for each of 24 combinations of the absolute neutrophil count and the proportion of immature neutrophils (c =0.80, 95% CI: 0.77, 0.83). Discrimination of the I/T2 improved with age, from 0.70 at <1 hour to 0.87 at ≥4 hours. However, 60% of I/T2 had likelihood ratios of 0.44 to 1.3, thus only minimally altering the pretest odds of disease. Calculating the I/T2 could enhance prediction of early onset sepsiss, but the CBC will remain helpful mainly when done at >4 hours of age and when the pretest probability of infection is close to the treatment threshold.