The value of neutrophil gelatinase-associated lipocalin and citrullinated alpha enolase peptide-1 antibody in diagnosis, classification, and prognosis for patients with sepsis
Authors: Hou Xiuzhu , Liu Chong , Lian Hongwei , Xu Zhen , Ma Lijuan , Zang Xubin , Sun Jianbin , Jia Keke , Cui Liyan 
Published: August 2020

Abstract
We examined the blood concentrations of neutrophil gelatinase-associated lipocalin (NGAL) and citrullinated alpha enolase peptide-1 (CEP-1) antibody in sepsis patients to evaluate their potential diagnostic, classified and prognostic utility together with C-reactive protein (CRP), procalcitonin (PCT), interleukin-6 (IL-6).
Sixty-nine patients admitted at the emergency department with sepsis were studied, on admission, their demographic and clinical information were recorded. Blood levels of CRP, PCT, IL-6, NGAL, and CEP-1 antibody were measured. Relationships between sequential [sepsis-related] organ failure assessment score and blood biomarkers, between acute physiology and chronic health evaluation II score and blood biomarkers were investigated. Additionally, the mutual correlation among CRP, PCT, IL-6, NGAL, and CEP-1 antibody were investigated. Diagnostic and predictive values for clinical outcomes for biomarkers were assessed by receiver operator characteristic curve.
Sixty-nine participants (38 sepsis, 31 septic shock) were compared with 40 healthy controls. The levels of CRP, PCT, IL-6, and NGAL were significantly higher in sepsis patients ([59.49 ± 48.88]; 0.71, [0.13–11.72]; 60.46, [33.26–201.20]; 265.61, [185.79–500.96], respectively) compared with healthy controls ([2.05 ± 1.85]; 0.02, [0.02–0.03]; 12.08, [7.22–16.84]; 19.73, [7.66–34.39], respectively) (P < .001). CRP, PCT, IL-6, and NGAL had better discriminatory performance with an area under the receiver operator characteristic curve (AUC) of (0.98; 0.98; 0.90; 0.97, respectively), 95% confidence interval (CI) = ([0.95; 1.00]; [0.96; 1.00]; [0.84; 0.96]; [0.94; 1.00], respectively) (P < .001), with a cut off value of (8.02 mg/L [Se = 88.40%, Sp = 100.00%]; 0.06 ng/mL [Se = 94.20%, Sp = 75.00%]; 30.63 pg/mL [Se = 78.30%, Sp = 95.00%]; 95.72 ng/mL [Se = 99.00%, Sp = 92.00%], respectively). Between the sepsis group and septic shock group, PCT and NGAL were significantly higher in septic shock group (2.44, [0.49–20.36]; 294.65 [203.34–1262.47], respectively) compared with sepsis group (0.41, [0.11–2.63]; 219.94, [146.38–385.24], respectively) (P < .05). Between survivors group and nonsurvivors group, PCT was obviously elevated in nonsurvivors group (2.47, [0.70–12.49]) compare with survivors group (0.41, [0.11–8.16]) (P < .05), with an AUC of 0.69, 95% CI = (0.57; 0.81) (P < .05), while CEP-1 antibody was decreased in nonsurvivors group (14.03, [4.94–17.17]) contrast to survivors group (18.78, [8.08–39.72]) (P < .05), with an AUC of 0.67, 95% CI = (0.54; 0.80) (P < .05). Additionally, CEP-1 antibody demonstrated a negative correlation with either sequential [sepsis-related] organ failure assessment score (r = −0.31, P < .05) or PCT (r = −0.27, P < .05).
As CRP, PCT, and IL-6, NGAL was valuable in sepsis diagnosis. With a classificatory value, PCT and NGAL correlated with the degree severity of sepsis. PCT and CEP-1 antibody were meaningful in sepsis prognosis. CEP-1 antibody may be a protective factor for sepsis.