Urinary neutrophil gelatinase-associated lipocalin in dogs: accuracy of a novel rapid test and biomarker behavior across clinical settings

Background Urinary neutrophil gelatinase-associated lipocalin (uNGAL) has emerged as an early marker of acute kidney injury (AKI) in dogs, but its measurement by ELISA is laborious in clinical practice.Hypothesis/Objectives Assess the performance of a novel point-of-care (POC) uNGAL assay for early detection of AKI in dogs and evaluate the clinical utility of uNGAL in differentiating AKI from other urinary conditions in dogs.Animals Urine supernatants from 200 client-owned dogs were collected and grouped as follows: healthy, chronic kidney disease (CKD), AKI (including AKI on CKD), urinary tract infections, urolithiasis, and extrarenal inflammatory diseases. Dogs then were classified by the presence (n = 39) or absence (n = 161) of AKI for calculation of diagnostic performance.Methods Urinary NGAL was measured using the Dog NGAL ELISA Kit (Bioporto) as the existing test and the "PRIMA Veterinary-KI screening test" (PRIMA Lab) as an index test.Results At the optimized cut-off of 20 ng/mL for the POC device, a sensitivity of 97.3% (95%CI, 85.8-99.9) and a specificity of 66.3% (95%CI, 58.4-73.5) for diagnosing AKI were found. For the ELISA, a sensitivity of 97.3% (95%CI, 85.8-99.9) and a specificity of 80.4% (95%CI, 73.4-86.2) were found. Cohen's kappa coefficient (kappa = 0.82) indicated an excellent agreement between methods.Conclusions and clinical importance With both methods, uNGAL showed moderate specificity and excellent sensitivity for the diagnosis of AKI. The POC device represents a clinically relevant diagnostic tool for screening AKI in patients at risk, given excellent agreement with the existing test.