Assessment of Renal Disease in Cats by Sdma, Creatinine Assessed by Population Reference Interval and Creatinine Assessed by Reference Change Value

Background: Symmetric dimethylarginine (SDMA) has recently been advocated as a marker to detect renal disease. Aims: This prospective study evaluated and compared the diagnosis of renal disease using SDMA, creatinine elevated above population derived reference intervals (RI) with dilute urine and creatinine in relation to an individual’s prior results (RCV). Results: Over the study period 214 concentrations of SDMA (range: 1 to 115 μg/dL) were determined from 177 cats. Creatinine concentrations (range: 51 to 1009 μmol/L) were available on all occasions; urine specific gravity (USG) was available on 146 occasions (range: 1.008 to 1.063). Percentage change values of creatinine (trend) were available on 150 occasions. SDMA, creatinine, creatinine trend and USG were all available on 108 occasions. SDMA was within the reported RI (0–14 μg/dL) on 135 occasions. Of these, creatinine by RI and RCV agreed on 104/135 (77%) and 52/89 (58%) occasions respectively. There were 34 discrepancies (25%), of which 29/135 (21%) were likely to have renal disease. SDMA was elevated (>14 μg/dL) on 79 occasions. Of cats with elevated SDMA, there were 28 discrepancies (35%), of which, 8 (10%) were unlikely to have renal disease. Conclusions: None of the methods alone were always reliable for detection of renal disease. Whether cats with creatinine elevated by RCV (and dilute urine) but without elevated creatinine (by RI) or elevated SDMA represent early detection of renal disease or false positives needs to be investigated further. Cats in this situation warrant further monitoring.