Tubular urinary biomarkers do not identify aetiology of acute kidney injury in kidney transplant recipients.

ABSTRACT

AIM: To evaluate the performance of urinary neutrophil gelatinase-associated lipocalin (uNGAL), kidney injury molecule, interleukin-18 and heat shock protein 72 for differential diagnosis between causes of acute kidney injury in kidney transplant recipients, especially immunological rejection. PATIENTS AND METHODS: We measured these biomarkers in 67 kidney transplant recipients with acute kidney injury according to the RIFLE criteria. RESULTS: There were no statistical differences in biomarkers between kidney transplant recipients with immunological rejection (n = 20), pre-renal causes (n = 20) and other AKI causes (n = 27). Only the uNGAL level relative to urinary creatinine (uNGAL/uCr) for immunological rejection was different in comparison with others (P < 0.001); a cut-off of 59 µg/g of uNGAL/uCr had a sensitivity and specificity of 60% and 58% respectively (area under the curve in receiver-operating characteristic curve, 0.65). The other biomarkers were not useful in differentiating the causes of acute kidney injury. CONCLUSION: The biomarkers tested are not useful in identifying immunological rejection as cause of acute kidney injury in kidney transplant recipients.