Urine Neutrophil Gelatinase-Associated Lipocalin Predicts Acute Kidney Injury

Despite the increasing heterogeneity of etiology, making a definitive and timely diagnosis of acute kidney injury (AKI) remains challenging. Currently, the diagnosis of AKI is still based on elevated serum creatinine concentration or decreased urinary excretion. However, increased serum creatinine and decreased urine volume usually occur 48 hours after renal injury.

Contrast-associated acute kidney injury (CA-AKI) is an early complication after percutaneous coronary intervention (PCI). Depending on the study subjects, the rate of acute kidney injury can occur from 4.2% to 50%. CA-AKI after PCI is often associated with contrast drugs, hemodynamic instability, old age, pre-existing chronic kidney disease, or a combination of diabetes and hypertension.

Medical Scientists at the Vietnam Military Medical University (Hanoi, Vietnam) included in a study 509 patients with chronic coronary artery disease, indicated for planned percutaneous coronary intervention at two centers. The patients were divided into two groups: group 1, 153 elderly patients ≥70 years old and group 2, 356 patients <70 years old. The team collected fasting morning venous blood plasma to determine concentrations of hs-CRP, hs-TnT, ALT, AST, cholesterol, triglyceride, HDL-C, LDL-C, electrolyte, glucose, urea, and creatinine.

The patient's 24 hour-urine sample was collected on the day before the procedure. After 24 hours, the team measures the urine volume, took 5 mL of urine to determine the neutrophil gelatinase-associated lipocalin (NGAL) level, and then calculated the 24-h urine NGAL concentration. Urine NGAL was measured by the Human Lipocalin-2/NGAL ELISA kit (BioVendor, Brno, Czech Republic) based on the sandwich enzyme immunoassay method. All patients had their glomerular filtration rate (eGFR) calculated based on the MDRD formula.

The investigators reported that the ratio of CA-AKI in group 1 was 23.5% which was higher than that of group 2 (8.7%). Urine NGAL level in group 1 was significantly higher than that of group 2 (31.3 (19.16–55.13) ng/mL versus 19.86 (13.21–29.04) ng/mL. At a cut-off value of 44.43 ng/ml, urinary NGAL had a predictive value for CA-AKI in all patients (AUC = 0.977). Especially at a cut-off value of 44.14 ng/mL, urinary NGAL had a predictive value for CA-AKI in elderly patients (AUC = 0.979).

The authors concluded that the rate of CA-AKI after PCI in elderly patients was 23.5%. Urine NGAL before PCI has a good predictive value for CA-AKI in elderly patients who received planned percutaneous coronary intervention. The study was published on November 10, 2022 in the Journal of Clinical Laboratory Analysis.

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