目的  探究腹膜透析(peritoneal dialysis，PD)合并感染性腹膜炎(septic peritonitis，SP)患者血清1磷酸鞘氨醇受体1(phosphatidylserine receptor 1，S1P1)、可溶性CD14亚型(soluble CD14 subtype，sCD14-ST)、应激诱导蛋白2(stress-induced protein 2，Sestrin2)水平变化及其诊断价值。 方法  选取2022年7月—2025年7月在深圳市龙岗中心医院收治的PD患者，根据是否合并SP分为SP组和非SP组。ELISA法检测血清S1P1、sCD14-ST、Sestrin2水平；Logistic回归分析影响因素；受试者工作特征(receiver operating characteristic，ROC)曲线分析诊断价值；Bootstrap法进行内部验证；Hosmer-Lemeshow检验模型拟合程度；决策分析曲线(decision analysis curve，DCA)评估诊断模型的临床实用性。 结果  本研究共纳入92例患者，其中SP组33例、非SP组59例。病原菌构成中，革兰氏阴性菌22株，占比62.86%；革兰氏阳性菌13株，占比37.14%。与非SP组相比，SP组血清C反应蛋白   (c-reactive protein，CRP)、sCD14-ST、Sestrin2水平升高，白蛋白(albumin，Alb)、S1P1水平降低(t=17.840、7.053、7.395、5.189、7.053，均P＜0.001)。血清S1P1(OR=0.493，95% CI：0.318～0.765，P=0.002)、sCD14-ST(OR=2.305，95% CI：1.202～4.419，P=0.012)、Sestrin2(OR=2.918，95% CI：1.416～6.014，P=0.004)水平是影响PD患者发生SP的因素；血清S1P1、sCD14-ST、Sestrin2水平单独与联合诊断PD患者合并SP的曲线下面积(area under curve，AUC)分别为0.887(95%CI：0.804～0.944)、0.796(95%CI：0.699～0.873)、0.801(95%CI：0.705～0.877)、0.948(95%CI：0.881～0.984)，联合诊断优于三者单独诊断(Z/P=2.079/0.038、2.948/0.003、2.893/0.004)。 结论  PD合并SP患者血清S1P1水平降低，sCD14-ST、Sestrin2水平升高，三者联合诊断PD患者合并SP效能更高。

Objective  To investigate the changes in serum levels of sphingosine‑1‑phosphate receptor 1 (S1P1), soluble CD14 subtype (sCD14‑ST), and stress‑induced protein 2 (Sestrin2) in peritoneal dialysis (PD) patients with septic peritonitis (SP), and to evaluate their diagnostic value.  Methods  PD patients treated at Shenzhen Longgang Central Hospital from July 2022 to July 2025 were enrolled and divided into an SP group and a non‑SP group according to the presence of SP. Serum levels of S1P1, sCD14‑ST, and Sestrin2 were measured by ELISA. Logistic regression was used to analyze influencing factors. Receiver operating characteristic (ROC) curve analysis was performed to evaluate diagnostic value. Internal validation was conducted using the Bootstrap method. Model calibration was assessed with the Hosmer‑Lemeshow test, and clinical utility was evaluated using decision curve analysis (DCA).  Results  A total of 92 patients were included, with 33 in the SP group and 59 in the non‑SP group. Among the pathogenic organisms, Gram‑negative bacteria accounted for 22 strains (62.86%) and Gram‑positive bacteria for 13 strains (37.14%). Compared with the non‑SP group, the SP group had significantly higher serum levels of C‑reactive protein (CRP), sCD14‑ST, and Sestrin2, and lower levels of albumin (Alb) and S1P1 (t = 17.840, 7.053, 7.395, 5.189, and 7.053, respectively, all  P＜0.001). Serum levels of S1P1 (OR=0.493, 95% CI: 0.318～0.765, P=0.002), sCD14‑ST (OR=2.305, 95% CI: 1.202～4.419, P=0.012), and Sestrin2 (OR=2.918, 95% CI: 1.416～6.014, P=0.004) were factors influencing the occurrence of SP in PD patients. The areas under the ROC curve (AUC) for S1P1, sCD14‑ST, Sestrin2 alone, and their combination in diagnosing SP in PD patients were 0.887～(95% CI: 0.804～0.944), 0.796 (95% CI: 0.699～0.873), 0.801 (95% CI: 0.705～0.877), and 0.948 (95% CI: 0.881～0.984), respectively. The combined diagnostic performance was superior to each individual marker (Z/P = 2.079/0.038, 2.948/0.003, and 2.893/0.004, respectively).  Conclusion  In PD patients with SP, serum S1P1 level is decreased, while sCD14‑ST and Sestrin2 levels are increased. The combination of these three markers demonstrates higher diagnostic efficacy for SP in PD patients.