Baseline urinary KIM-1 concentration in detecting acute kidney injury should be interpreted with patient pre-existing nephropathy.

•The correlation of urinary KIM-1 with pre-existing evidence of nephropathy such as proteinuria, hematuria and pyuria was investigated.•Urinary KIM-1 was normalized to urine creatinine concentration.•Urinary KIM-1 reference intervals for healthy adults with normal kidney filtration and without proteinuria were established.•Age and sex effects on the urinary KIM-1 concentration were investigated.