The relationship between serum neutrophil gelatinase-associated lipocalin and renal function in patients with vancomycin treatment.

Background Vancomycin is used for the treatment of resistant staphylococcal and enterococcal infections but is associated with nephrotoxicity. Neutrophil gelatinase-associated lipocalin (NGAL) was recently identified as a sensitive biomarker for acute kidney injury. Here, we aimed to investigate the usefulness of serum NGAL in monitoring patients undergoing vancomycin therapy. Methods A total of 253 NGAL tests from 59 patients undergoing vancomycin therapy were evaluated. Patients with trough serum concentrations of vancomycin that exceeded 20 ug/mL were included. Serum NGAL was measured using a commercially available ELISA kit, and other biochemical indicators including creatinine, leukocyte count, eGFR and C-reactive protein were assessed. Results At the initiation of vancomycin treatment, serum creatinine level was 0.93 ± 0.40 (mean ± SD) mg/dL, NGAL was 341 ± 354 mg/dL, leukocyte count was 10,750 ± 7190 per uL and CRP level was high (10.8 ± 9.3 mg/dL). About 49% of patients had an elevated leukocyte count, and all patients showed a high CRP level. Basal serum NGAL concentration in the patients with elevated leukocyte level (10,000/uL or higher) was higher compared to that in patients with normal leukocyte levels (mean ± SD, 478 ± 449 mg/dL vs. 176 ± 101 mg/dL, p<0.001). A significant positive relationship was found between NGAL level and creatinine level in patients with normal basal leukocyte levels but not in those with higher leukocytes. Conclusion The clinical usefulness of serum NGAL should be interpreted carefully when evaluating renal impairment in patients undergoing vancomycin treatment.