Serum neutrophil gelatinase-associated lipocalin as a predictor of renal injury in patients with multiple myeloma

Background Multiple myeloma (MM) is a hematologic malignancy often complicated by renal impairment (RI), which worsens prognosis. Serum creatinine (sCr) is a late marker of kidney injury. Neutrophil gelatinase-associated lipocalin (NGAL) is an early biomarker of tubular injury that may improve RI detection in MM. Aim To evaluate serum NGAL as a predictor of renal injury and its relationship with renal function in MM cases. Methods This prospective case–control research involved 60 MM cases and 30 healthy controls. Clinical evaluation, laboratory tests, and imaging were performed. Serum NGAL levels were measured using ELISA. Renal function was assessed by serum creatinine and estimated glomerular filtration rate. Statistical analysis involved correlation, receiver operating characteristic curves, and regression analysis. Results Serum NGAL was significantly higher in MM patients than controls (400.86 ± 169.78 vs. 111.04 ± 51.63 ng/ml, P below 0.001). Receiver operating characteristic analysis illustrated excellent diagnostic accuracy (area under the curve=0.991) at a cutoff greater than 203.09 ng/ml, with 98.3% sensitivity and 96.7% specificity. NGAL levels increased with worsening glomerular filtration rate ( P =0.003) and were lower in patients achieving complete/partial response than those with stable/progressive illness ( P =0.032). No significant differences were found by chemotherapy regimen, radiotherapy status, Bence Jones protein presence, or M-protein type. Conclusion Serum NGAL is a sensitive and early indicator of renal injury in MM, correlating with renal function and treatment response. Its integration into clinical practice could improve early detection, risk stratification, and monitoring of renal outcomes in MM cases.