本病例对照研究旨在评估健康和住院奶牛的降钙素原（PCT）血浆浓度，并对细菌感染引起的炎症做出结论性诊断。包括34头健康奶牛和131头患病奶牛。使用用于牛的ELISA试剂盒评估降钙素原浓度。根据患病奶牛在入院前是否接受了抗菌治疗，他们分为治疗组(TP)或未治疗组(NTP).进行了Mann-WhitneyU测试，以确定健康奶牛与患病奶牛之间的差异，而Kruskal-Wallis与Dunn的多重比较检验适用于健康与患病亚组。进行接收器工作特性(ROC)分析以评估最佳截止值。确定了属于PCT值低于和高于ROC截止值的组的奶牛的Kaplan-Meier存活曲线。健康对照组和患病组的血浆PCT浓度分别为200.1（147.8-324.1）pg/mL和361.6（239.7-947.1）pg/mL，分别(P<0.001)。血浆PCT浓度的最佳临界值为244.4pg/mL(灵敏度73.6%,特异性60.0%)。TP亚组的血浆PCT浓度为267.5（210.3-771.2）pg/mL，NTP亚组为425.6（253.1-1242）pg/mL（P=0.03）。PCT高于ROC截断值的奶牛生存率降低，死亡风险较高（P<0.05）。降钙素原显示出区分健康母牛与住院母牛的能力，并最终诊断出由于细菌感染引起的炎症。此外，PCT是阴性预后结果的良好预测因子。
This
case - control study aims to evaluate Procalcitonin (PCT) plasma concentrations in healthy and hospitalized cows with a conclusive diagnosis of inflammation due to bacterial infection. Thirty-four healthy and 131 sick cows were included. Procalcitonin concentrations were assessed using an ELISA kit for cattle. Depending on whether sick cows received antimicrobial treatments prior to admission or not, they were divided in treated (TP) or not treated (NTP) subgroups. Mann-Whitney U tests were performed to determine differences between healthy vs sick cows, while Kruskal-Wallis with Dunn\'s multiple comparison test were applied for healthy vs sick subgroups. Receiver operating characteristic (ROC) analysis was performed to assess the optimal cut-off value. Kaplan-Meier survival curves were determined for cows belonging to the groups with PCT values below and above ROC cut-offs. Plasma PCT concentration was 200.1 (147.8-324.1) pg/mL and 361.6 (239.7-947.1) pg/mL in the healthy control and in the sick group, respectively (P < 0.001). The optimal cut-off value of plasma PCT concentration was 244.4 pg/mL (sensitivity 73.6%, specificity 60.0%). The plasma PCT concentration was 267.5 (210.3-771.2) pg/mL in the TP subgroup and 425.6 (253.1-1242) pg/mL in the NTP subgroup (P = 0.03). Cows with PCT above the ROC cut-off value had a reduced survival percentage and a higher mortality risk (P < 0.05). Procalcitonin showed the ability of differentiate healthy cows from hospitalized cows with a conclusive diagnosis of inflammation due to bacterial infection. Moreover, PCT was a good predictor of negative prognostic outcome.
