T L Williams1, J Archer1. 1. Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES.
Abstract
OBJECTIVES: Evaluation of urine albumin:creatinine ratio, urine cystatin C:creatinine ratio, urine protein:creatinine ratio and urine specific gravity as screening tests for azotaemic chronic kidney disease in cats. METHODS: A group of cats over eight years old were defined as either (i) healthy non-azotaemic (n=40) if they had serum creatinine concentration <153 µmol/L and no history of apparent disease or (2) having azotaemic chronic kidney disease (n=12) if they had serum creatinine concentration >153 µmol/L with urine specific gravity <1·035. Urine albumin:creatinine ratio, urine cystatin C:creatinine ratio, urine protein:creatinine ratio and urine specific gravity were compared between the two groups. RESULTS: Urine cystatin C:creatinine ratio was significantly lower in cats with azotaemic chronic kidney disease than that in healthy cats [3·7 (1·4, 4·3)×10(-6) versus 13·9 (6·3, 24·7)×10(-6) ; P=0·011]. Urine specific gravity was also significantly lower in the azotaemic chronic kidney disease group than that in the healthy group [1·022 (1·017, 1·028) versus 1·043 (1·034, >1·050); P<0·001]. Urine albumin:creatinine ratio and urine protein:creatinine ratio were not significantly different between the groups (P=0·075 and P=0·965, respectively). CLINICAL SIGNIFICANCE: Urine cystatin C:creatinine ratio and urine specific gravity were significantly lower in cats with azotaemic chronic kidney disease than that in healthy cats; however, neither biomarker was an adequate sole screening test for azotaemic chronic kidney disease.
OBJECTIVES: Evaluation of urine albumin:creatinine ratio, urine cystatin C:creatinine ratio, urine protein:creatinine ratio and urine specific gravity as screening tests for azotaemic chronic kidney disease in cats. METHODS: A group of cats over eight years old were defined as either (i) healthy non-azotaemic (n=40) if they had serum creatinine concentration <153 µmol/L and no history of apparent disease or (2) having azotaemic chronic kidney disease (n=12) if they had serum creatinine concentration >153 µmol/L with urine specific gravity <1·035. Urine albumin:creatinine ratio, urine cystatin C:creatinine ratio, urine protein:creatinine ratio and urine specific gravity were compared between the two groups. RESULTS: Urine cystatin C:creatinine ratio was significantly lower in cats with azotaemic chronic kidney disease than that in healthy cats [3·7 (1·4, 4·3)×10(-6) versus 13·9 (6·3, 24·7)×10(-6) ; P=0·011]. Urine specific gravity was also significantly lower in the azotaemic chronic kidney disease group than that in the healthy group [1·022 (1·017, 1·028) versus 1·043 (1·034, >1·050); P<0·001]. Urine albumin:creatinine ratio and urine protein:creatinine ratio were not significantly different between the groups (P=0·075 and P=0·965, respectively). CLINICAL SIGNIFICANCE: Urine cystatin C:creatinine ratio and urine specific gravity were significantly lower in cats with azotaemic chronic kidney disease than that in healthy cats; however, neither biomarker was an adequate sole screening test for azotaemic chronic kidney disease.