Early detection of decreased glomerular filtration rate (GFR) in dogs is difficult. Current methods are insensitive and reference ranges are wide. More sensitive biomarkers are warranted. The aim of this study was to investigate the usefulness of the new marker symmetric dimethylarginine (SDMA) in comparison with creatinine for detection of decreased GFR in dogs with and without a stable diagnosis of chronic kidney disease (CKD).

Ninety-seven client-owned dogs were prospectively included into the study, 67 dogs with a diagnosis (or a strong suspicion) of CKD, and 30 healthy dogs. All dogs underwent physical examination, blood pressure measurements, urinalysis, hematology and blood biochemistry, cardiac and urinary ultrasound examinations, and scintigraphy for calculation of glomerular filtration rate (mGFR). Decreased mGFR was predefined as <30.8 ml/min/L and it was normalized to estimated extra-cellular plasma volume (ECFV) instead of body weight because of less dependency on hydration status of the dog. Estimation of ECFV was performed according to routine using the Rutland-Patlak plot, a mathematical model that describes the transfer of ^99mTechnetium-DTPA from the blood compartment to the renal compartment.

Creatinine and SDMA were positively correlated (r=0.82). The reciprocal of creatinine and SDMA were both linearly correlated with GFR (R²=0.62 and 0.55, respectively). The sensitivity of creatinine and SDMA at their pre-specified cut-offs (46–115 µmol/L and 0–14 µg/dl, respectively) for detection of an abnormal GFR was exactly the same (89.7%) in the dogs of this study. The specificity was 89.7% for creatinine and 86.8% for SDMA.

In conclusion, the diagnostic performance of creatinine and SDMA, when using their pre-specified cut-offs, for detection of a decreased GFR in the dogs of this study was similar.

Disclosures

No disclosures to report.