Urinary calprotectin, NGAL, and KIM-1 in the differentiation of primarily inflammatory vs. non-inflammatory stable chronic kidney diseases

Abstract

Introduction It has been demonstrated that urinary neutrophil gelatinase-associated lipocalin (NGAL) and calprotectin are helpful biomarkers in the differentiation of intrinsic and prerenal acute kidney injury. Objective The present cross-sectional study investigates, whether urinary biomarkers are able to differentiate primarily inflammatory from non-inflammatory entities in chronic kidney disease (CKD). Methods Urinary calprotectin, NGAL, and kidney injury molecule-1 (KIM-1) concentrations were assessed in a study population of 143 patients with stable CKD and 29 healthy controls. Stable renal function was defined as an eGFR fluctuation ≤5 ml/min/1.73 m2 in the past 12 months. Pyuria, metastatic carcinoma, and renal transplantation were regarded as exclusion criteria. Diabetic nephropathy, hypertensive nephropathy, and polycystic kidney disease were categorized as ‘primarily non-inflammatory renal diseases’ (NIRD), whereas glomerulonephritis and vasculitis were regarded as ‘primarily inflammatory renal diseases’ (IRD). Results Urinary calprotectin and NGAL concentrations significantly differed between CKD and healthy controls (p 0.05 each). Albumin exceeds the diagnostic power of the investigated biomarkers by far. Conclusions The urinary biomarkers calprotectin, NGAL, and KIM-1 have no diagnostic value in the differentiation of primarily inflammatory vs. non-inflammatory etiologies of CKD.

Keywords

• calprotectin
• chronic kidney disease
• kim-1
• ngal