LAUSR

BACKGROUND Neutrophil gelatinase-associated lipocalin (NGAL) is produced in response to inflammation in horses, but it has not yet been investigated as a biomarker in horses with abdominal disease. OBJECTIVES To investigate NGAL in serum and peritoneal fluid in horses with abdominal disease. STUDY DESIGN Retrospective clinical study. METHODS Data from medical records of 270 horses admitted with acute abdominal disease (simple obstructions [n=43], strangulating obstructions [n=104], inflammatory abdominal disease [n=99], non-strangulating intestinal infarction [NSII, n=24]) and 9 healthy control horses were reviewed, and serum and peritoneal fluid samples were retrieved from a biobank. NGAL was measured in serum and peritoneal fluid by ELISA. Differences in NGAL concentrations between groups were assessed. RESULTS Healthy horses had low serum and peritoneal fluid concentrations of NGAL (median = 21.0 and 9.5 μg/L, respectively). Neither serum nor peritoneal fluid NGAL concentrations (median serum, peritoneal fluid) differed between healthy horses and horses with simple (28.1 μg/L, 13.0 μg/L) and strangulating intestinal obstructions (34.7 μg/L, 38.4 μg/L). Horses with NSII (308.0 μg/L, 2163.0 μg/L) and inflammatory abdominal disease (171.1 μg/L, 314.1 μg/L) had higher serum and peritoneal fluid concentrations of NGAL than the other groups (P<0.001). Peritoneal fluid NGAL concentrations in horses with NSII were higher than in horses with inflammatory abdominal disease (P=0.03). MAIN LIMITATIONS Retrospective study design; small group of control horses. CONCLUSIONS NGAL is a marker of inflammation in horses with abdominal disease. The high peritoneal fluid concentration of NGAL in horses with NSII compared to all other groups may render NGAL useful for identifying this condition, which is otherwise difficult to differentiate from other types of peritonitis. Thereby, NGAL may potentially facilitate timely surgical intervention in this group of patients. The results of this study must be evaluated in larger, and preferably prospective, studies to obtain a more comprehensive evaluation of the diagnostic utility of NGAL. This article is protected by copyright. All rights reserved.