Background: Neutrophil gelatinase-associated lipocalin (NGAL) is a promising biomarker in humans and dogs with kidney disease. This protein is expressed by many cells including renal tubular cells and neutrophils. The aim of this study was to evaluate the effect of urinary tract infection (UTI) on urinary NGAL (uNGAL) concentration in dogs.
Methods: Urine culture and measurement of uNGAL level were performed in 80 non-azotemic dogs suspected of UTI and 19 healthy dogs. Dogs were divided in three groups: 19 healthy dogs, 25 dogs with positive culture and 55 dogs suspected of UTI but with negative culture.
Results: uNGAL and uNGAL/Creatinine was significantly higher (P<0.0001) in dogs with UTI (14.22ng/mL;19.74μg/g) compared to Healthy (0.24ng/mL;0.11μg/g) and Negative (1.13ng/mL;1.28μg/g) dogs. A uNGAL value <3.38ng/mL had a negative predictive value for UTI of 87%.
Conclusion: Presence of UTI has to be considered when uNGAL is used to detect kidney disease.