Effluent lipopolysaccharide is a prompt marker of peritoneal dialysis-related gram-negative peritonitis

To investigate the value of effluent lipopolysaccharide (LPS) for early detection of gram-negative peritonitis (GNP) in peritoneal dialysis (PD) patients.

PD-related peritonitis episodes occurring between January 2016 and December 2018 were included in the study. Effluent LPS and the other infectious parameters were measured at peritonitis presentation, and peritonitis was categorized as GNP, non-GNP, and culture-negative peritonitis. Receiver operating characteristic (ROC) analysis was employed to evaluate the efficacy of effluent LPS to distinguish GNP.

A total of 161 peritonitis episodes were analyzed, including 49 GNP episodes and 82 non-GNP episodes. In contrast with non-GNP, GNP presented with higher effluent leukocyte count (3236 (1497-6144) vs. 1904 (679-4071) cell mm^-3, p = 0.008), increased effluent LPS (1.552 (0.502-2.500) vs. 0.016 (0.010-0.030) EU mL^-1, p < 0.001), lower blood leukocyte count (9.95 ± 3.18 vs. 11.56 ± 4.37 × 10⁹ L^-1, p = 0.017), greater neutrophil predominance (87.1 ± 4.6% vs. 83.4 ± 7.7%, p = 0.001), and greater "procalcitonin" (PCT, 4.90 (2.20-12.60) vs. 1.00 (0.51-4.07) µg L^-1, p < 0.001). It took 5.2 ± 3.1 h to report the results of effluent LPS. Effluent LPS cutoff value of >0.035 EU mL^-1 showed an area under the ROC curve of 0.972 (95% CI 0.951-0.994, p < 0.001) in differentiating GNP from non-GNP with a sensitivity of 100% and a specificity of 80.5%, and its joint utilization with PCT further increased the specificity (91.4%) to discriminate GNP.

PD effluent LPS could be an applicable early marker of gram-negative organism-related peritonitis in PD patients.