Kidney injury molecule-1 as a biomarker of acute kidney injury in renal transplant recipients.

This Practice Point commentary discusses a study by Zhang and colleagues that investigated the usefulness of kidney injury molecule-1 (KIM-1) for the early diagnosis of tubular injury on renal biopsy. The study found that KIM-1 protein expression was present in 100% of biopsies that showed acute tubular injury, and in 28% of protocol kidney biopsies that showed no morphological pathology. KIM-1 levels showed positive correlation with serum creatinine and blood urea nitrogen levels, and inverse correlation with estimated glomerular filtration rate. We discuss the findings of Zhang et al., and describe other potential biomarkers for detecting early tubular injury that are currently under investigation. KIM-1, potentially in combination with other biomarkers, might be useful for diagnosing early acute tubular injury on renal biopsy, and might also be of prognostic significance.