This use of a KIM-1:creatinine ratio was slightly superior to KIM-1 concentration for the detection of AKI in humans.13 In humans, urine KIM-1 increases with proteinuria.7 However, this finding was reported in humans with diabetic nephropathy, a population that generally has more proteinuria than the relatively mild values seen in cats with CKD, and results therefore may not be comparable.13,16 The association of nKIM-1 with 1+ proteinuria is suspected to be spurious, as it is not physiologically plausible that nKIM-1 relates only to specific degrees of proteinuria. This evidence concerns the gene HAVCR1 and acute kidney injury.