Clinical utility of urine kidney injury molecule-1 (KIM-1) and gamma-glutamyl transferase (GGT) in the diagnosis of canine acute kidney injury

The aim of the present study was to evaluate the sensitivity and specificity of urine KIM-1 and urine GGT for the detection of naturally-occurring AKI, compared to healthy control dogs, dogs with stable chronic kidney disease (CKD), and dogs with lower urinary tract disorders (LUTD). The study included AKI grade 1 (n = 21), AKI grade 2 to 5 (n = 11), stable CKD (n = 11), LUTD (n = 15), and healthy dogs (n = 37). Urine KIM-1 (ng/mg) and GGT (U/l) were normalized to urine creatinine (uCr). Statistically significant difference in KIM/uCr (p = 0.0007) and GGT/uCr (p < 0.0001) was found among the study groups. Area under the curve (AUC) for KIM-1/uCr and GGT/uCr as predictors of AKI was 0.81 and 0.91 respectively. Values of KIM-1/uCr of 0.73 ng/mg and of GGT/uCr of 54.33 showed the best combination of sensitivity and specificity (75% and 75.6%; 85.7% and 89.1% respectively). A significant positive correlation (p < 0.0001) between KIM-1/uCr and GGT/uCr was found. Both urine KIM-1/uCr and GGT/uCr seemed to be potentially good markers for the diagnosis of AKI. Dogs with AKI showed significantly higher levels of urine KIM-1/uCr and urine GGT/uCr, compared with healthy dogs. Caution should be used in the evaluation of elevated urine KIM-1/uCr and GGT/uCr in dogs with pre-existing CKD and/or LUTD. Urine KIM-1/uCr and GGT/uCr might have a significant clinical utility, as complementary test, particularly in diagnosis early, non-azotemic stages of AKI.