VALIDATION OF AN ELECTROPHORETIC METHOD TO DETECT URINARY ALBUMIN IN CATS.

Urine samples were collected from 66 feline hospital admissions by cystocentesis or free catch, and analyzed (UPC, HRE). Within-assay imprecision for high (H), medium (M) and low (L) concentrations, between-assay imprecision, linearity/accuracy and percentage recovery were determined for albumin. Albumin was assessed by urine to creatinine ratio (UAC), percentage (ALB%) and mg/dl (ALB mg/dl). Cases were categorized: a) as chronic kidney disease with (CKDC) and without complications (CKD), feline lower urinary tract disease (FLUTD) or other, and b) as proteinuric (P), borderline proteinuric (BP), or not proteinuric (NP), and c) by type of sediment active (A) or not active (NA). Results: HRE within-assay CV was 2.58%(H), 5.31%(M), 3.42%(L), between-assay CV was 3.52%, recovery percentage was 97%, 93% and 109% for high, medium and low concentration, respectively, and linearity was high (r=0.99). Compared with UPC at different cut-off values, HRE showed higher specificity and PPV but lower sensitivity and NPV than dipstick to measure proteinuria. Dipsticks showed frequent false positives compared with HRE. Based on UPC, measures of albuminuria were higher in proteinurics than non-proteinurics, and ALB% correlated to UPC (r=0.35, R2=0.12, p<0.05) and UAC (r=0.41, R2=0.17, p<0.05). Samples with active sediment had higher ALB% than samples with inactive sediment. ALB% was not different between proteinuria groups (P, BP, NP). UPC, UAC, ALB mg/dl, ALB% were not different across pathologies, even if CKD had higher values. Conclusions: HRE is accurate and precise for measuring urinary albumin in cats. UPC, UAC and ALB% were correlated. Increases in filtered albumin and proteinuria indicate a greater glomerular involvement in renal disease.