Urine dipstick test not accurate for detecting proteinuria in cats even when associated with urine-specific gravity

23/09/2020

A new study, published in the latest issue of JSAP, showed that the urine dipstick test was not accurate for detecting proteinuria alone, or when combined with the urine-specific gravity (USG) in cats....
 

The study titled “The utility of combined urine dipstick analysis and specific gravity measurement to determine feline proteinuria” assessed the utility of the urine dipstick alone and combined with the urine-specific gravity (USG) for detecting proteinuria in cats.

The clinical records of cats presenting to a referral hospital between January 2011 and January 2017 were retrospectively reviewed. To be eligible for inclusion in the study, feline urine samples must have undergone a complete urinalysis including dipstick evaluation, USG and urine protein-to-creatinine (UPC) measurement. A total of 121 urine samples were included and diagnostic agreement and test accuracy were calculated for the dipstick test alone and in combination with the USG, using different cut-off values for proteinuria. Receiver-operating characteristic (ROC) curves were also calculated.

Jorge Pérez-Accino, corresponding author for the paper, said: “The diagnostic agreement between the urine dipstick and UPC ratio was poor and did not improve if the USG was considered together with the dipstick. A dipstick result of equal or greater than “Trace” (0.1-0.3g/L) had a sensitivity of 81% and a specificity of 31% to detect proteinuria. With regards the ROC curves, the area under the curve (AUC) of the urine dipstick alone was poor (0.57). When combined with the USG results, this improved to fair (0.78) but the specificity and negative predictive value (NPV) were still low.”

Nicola Di Girolamo, Editor of JSAP concluded: “These findings indicate that clinicians should not rely on the results of the urine dipstick test in combination with USG in cats for detecting proteinuria. Instead other quantitative methods, such as UPC ratio, should always be performed to detect proteinuria in cats.”

J. Pérez-Accino, L. F. Bernabe, E. G. Manzanilla and J. Puig (2020) The utility of combined urine dipstick analysis and specific gravity measurement to determine feline proteinuria. Journal of Small Animal Practice 61 (9). Available at: https://onlinelibrary.wiley.com/doi/10.1111/jsap.13184

The BSAVA has put together a collection of resources relating to urinalysis and proteinuria, available here: https://www.bsavalibrary.com/content/urinalysis--160

(Image: Courtesy of Ian Ramsey BVSc, PhD, DSAM, DipECVIM-CA FHEA, FRCVS, BSAVA President 2020/2021)