腹水是指病理性液体在腹腔内的积聚，其根源有两个主要原因。一类是恶性疾病，例如肝癌或胰腺癌等；另一类是良性疾病，如肝硬化和心衰。本研究旨在研究芳酰酯酶（ARES）、对映磷酰化酶（PON）、刺激对映磷酰化酶（SPON）、过氧化氢酶（CAT）和髓过氧化物酶（MPO）在区分恶性和良性腹水的诊断效用。该研究于2016年2月至9月进行。排除急性感染、服用维生素补充剂和抗氧化药物、吸烟和饮酒者。研究对象为60位患者，其中36位为良性腹水患者（60%）、24位为恶性腹水患者（40%）。患者的平均年龄为63.3岁。恶性患者中MPO水平（14.2 vs. 4.2；p=0.028）较高，而PON（2.6 vs. 4.5；p<0.001）、SPON（10.7 vs. 23.9；p<0.001）、ARES（615.7 vs. 823.5，p<0.001）和CAT（13.3 vs. 36.8；p=0.044）水平较低。PON、SPON和ARES水平之间存在正相关性，而MPO水平与SPON、ARES和CAT水平之间存在负相关性。与ARES和CAT水平相比，MPO水平在预测恶性程度方面具有更好的诊断性能（p<0.05），但与PON和SPON水平相比，其诊断优势不明显（p>0.05）。PON、SPON、ARES、CAT和MPO可以在高灵敏度和高特异度的情况下用于恶性和良性腹水的区分诊断。

Ascites is the pathological fluid accumulation in the peritoneal cavity and there are mainly two reasons for its etiology. These are malignant diseases such as hepatoma or pancreas cancer and benign diseases such as liver cirrhosis and heart failure. In this study, we investigated the diagnostic utility of arylesterase (ARES), paraoxonase (PON), stimulated paraoxonase (SPON), catalase (CAT) and myeloperoxidase (MPO) in the differential diagnosis of malignant and benign ascites.This study was conducted between February and September 2016. Patients with acute infection, those taking vitamin supplements and antioxidant medication, smoking, and drinking alcohol were excluded from the study.The study population consisted of 60 patients: 36 had benign (60%) and 24 had malignant (40%) ascites. The mean age of the patients was 63.3 years. MPO levels (14.2 vs. 4.2; p=0.028) were found to be higher and PON (2.6 vs. 4.5; p<0.001), SPON (10.7 vs. 23.9; p<0.001), ARES (615.7 vs. 823.5, p<0.001) and CAT (13.3 vs. 36.8; p=0.044) were found to be lower in malignant patients compared to benign patients. There was a positive correlation between PON, SPON, and ARES levels, and a negative correlation between MPO levels and SPON, ARES, and CAT levels. MPO levels showed superior diagnostic performance compared to ARES and CAT levels (p<0.05) for predicting malignancy but showed no diagnostic superiority compared to PON and SPON levels (p>0.05).PON, SPON, ARES, CAT, and MPO can be used with high sensitivity and specificity in the differential diagnosis of malignant and benign ascites.