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

Abstract

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 (κ = 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.