Neutrophil gelatinase-associated lipocalin (NGAL) correlations with cystatin C, serum creatinine and eGFR in patients with normal serum creatinine undergoing coronary angiography.

Sir, Neutrophil gelatinase-associated lipocalin (NGAL), a memberof the lipocalin family, is readily excreted and detected inurine, due to its small molecular size (25 kDa) and resistanceto degradation. NGAL is highly accumulated in the human kidneycortical tubules, blood and urine, after nephrotoxic and ischaemicinjuries [1]. Thus, NGAL might represent an early, sensitive,non-invasive biomarker for acute renal injury [2], and urinaryNGAL might serve as an early marker for ischaemic renal injuryin children after cardiopulmonary bypass [3]. On the other hand,serum cystatin C was proposed as a new marker of glomerularfiltration rate (GFR), even in chronic kidney disease [4]. CystatinC has a low molecular weight (13 kDa) and is freely filtered