CKD KIM-1 Medicine NGAL Polyomavirus associated nephropathy T-cell-mediated rejection acute kidney injury acute rejection acute tubulointerstitial nephritis antibody-mediated rejection arterial hypertension biomarker biomarkers calcineurin-inhibitor nephrotoxicity cardiovascular disease chronic allograft dysfunction chronic kidney disease chronic rejection cystatin C cystatin-C diabetic kidney disease diagnostic test accuracy differential diagnosis end-stage kidney disease (ESKD) epidemiology exercise extracellular vesicles functional assessment furosemide stress test gentamicin