Supplementary Material for: Procalcitonin for Detecting Culture-Positive Sepsis in Neonates: A Prospective, Multicenter Study

<b><i>Introduction:</i></b> It is unclear if serum procalcitonin (PCT) estimated at sepsis suspicion can help detect culture-positive sepsis in neonates. We evaluated the diagnostic performance of PCT in culture-positive sepsis in neonates. <b><i>Methods:</i></b> This was a prospective study (February 2016 to September 2020) conducted in four level-3 units in India. We enrolled neonates suspected of sepsis in the first 28 days of life. Neonates with birth weight &lt;750 g, asphyxia, shock, and major malformations were excluded. Blood for PCT assay was drawn along with the blood culture at the time of suspicion of sepsis and before antibiotic initiation. The investigators labeled the neonates as having culture-positive sepsis or “no sepsis” based on the culture reports and clinical course. PCT assay was performed by electrochemiluminescence immunoassay, and the clinicians were masked to the PCT levels while assigning the label of sepsis. Primary outcomes were the sensitivity, specificity, and likelihood ratios to identify culture-positive sepsis. <b><i>Results:</i></b> The mean birth weight (SD) and median gestation (IQR) were 2,113 (727) g and 36 (32–38) weeks, respectively. Of the 1,204 neonates with eligible cultures, 155 (12.9%) had culture-positive sepsis. Most (79.4%) were culture-positive within 72 h of birth. The sensitivity, specificity, and positive and negative likelihood ratios at 2 ng/mL PCT threshold were 52.3% (95% confidence interval: 44.1–60.3), 64.5% (60.7–68.1), 1.47 (1.23–1.76), and 0.74 (0.62–0.88), respectively. Adding PCT to assessing neonates with 12.9% pretest probability of sepsis generated posttest probabilities of 18% and 10% for positive and negative test results, respectively. <b><i>Conclusion:</i></b> Serum PCT did not reliably identify culture-positive sepsis in neonates.

**引言**：当临床怀疑新生儿脓毒症时，检测血清降钙素原（procalcitonin, PCT）是否有助于识别血培养阳性脓毒症，目前尚不明确。本研究旨在评估PCT对新生儿血培养阳性脓毒症的诊断效能。**方法**：本研究为前瞻性队列研究，于2016年2月至2020年9月在印度4个新生儿科三级病区开展。研究纳入出生后28天内临床怀疑脓毒症的新生儿。排除出生体重低于750g、存在窒息、休克或严重畸形的新生儿。在临床怀疑脓毒症时、启动抗生素治疗前，采集血液标本用于PCT检测及血培养。研究人员根据血培养结果及临床病程将新生儿分为血培养阳性脓毒症组与"无脓毒症"组。PCT检测采用电化学发光免疫分析法，临床医师在进行脓毒症诊断分组时对PCT检测结果设盲。本研究的主要结局指标为识别血培养阳性脓毒症的灵敏度、特异度及似然比。**结果**：研究对象的平均出生体重（标准差，SD）为2113（727）g，中位孕周（四分位数间距，IQR）为36（32~38）周。在1204名完成合格血培养的新生儿中，155例（12.9%）确诊为血培养阳性脓毒症。其中79.4%的患儿在出生后72小时内血培养即呈阳性。当PCT截断值设定为2ng/mL时，其识别血培养阳性脓毒症的灵敏度为52.3%（95%置信区间：44.1~60.3），特异度为64.5%（60.7~68.1），阳性似然比为1.47（1.23~1.76），阴性似然比为0.74（0.62~0.88）。在脓毒症验前概率为12.9%的新生儿中，加入PCT检测后，阳性检测结果对应的验后概率为18%，阴性检测结果对应的验后概率为10%。**结论**：血清PCT无法可靠识别新生儿血培养阳性脓毒症。