AKI is associated with high mortality, partially due to its late recognition using available markers. Current research aims to identify new AKI biomarkers; however, their specificity is hampered when these are also expressed in extra-renal tissues. Recently, assays were developed for kidney-specific urinary clusterin (uClus) and serum and urine cystatin B (sCysB, uCysB, respectively). To assess their utility, 40 dogs were recruited and categorized to heathy controls, chronic kidney disease (CKD), AKI and UTI.

Median uClus/uCr was 40 ng/mg (range 3–157), 43 (12–6189), 1740 (391–11834) and 6964 (102–69855) in control, UTI, CKD and AKI groups, respectively. It differentiated control and AKI (receiver operating [ROC] area under curve [AUC] 0.96, CI95%, 0.88–1.00). ROC analysis applied to all dogs, had an AUC of 0.86, (CI95%, 0.72–0.97). A cut-off of 3380 ng/mg resulted in 80% sensitivity and 90% specificity. Median sCysB was 206 ng/ml (range 113–291), 608 ng/ml (200–1348) and 1763 ng/ml (604–4175), in control, CKD and AKI groups, respectively. It differentiated control and AKI (AUC 1.0, CI95% 1.00–1.00). ROC analysis applied to all dogs showed AUC of 0.91 (CI95% 0.79–1.00). A 700 ng/ml cut-off, gave 88% sensitivity and 86% specificity. ROC analysis of uCysB comparing AKI to all other groups gave an AUC of 0.87 (CI95% 0.74–1.00). A 485 ng/ml cut-off was associated with sensitivity and specificity of 79% and 83%, respectively.

In conclusion, these novel kidney-specific biomarkers differentiated AKI from heathy controls and other urinary tract conditions. Their specificity is a major advantage compared to previously reported biomarkers.

Disclosures

Disclosures to report:

Farace, J. Quinn, M. Yerramilli, M. Yerramilli are Employees of IDEXX Laboratories, Inc., Westbrook, ME, USA