Distribuzione delle concentrazioni di lipocalina associata alla gelatinasi dei neutrofili (NGAL) nelle urine di soggetti con funzionalità renale in ambito fisiologico

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ABSTRACT

Urinary neutrophil gelatinase-associated lipocalin (NGAL) concentrations in subjects with preserved renal function

The role of NGAL as an early and sensitive biomarker of acute kidney injury (AKI) has been confirmed in several studies, but its sensibility in highlighting subclinical renal tubular dysfunction is still uncertain. The NGAL biological variability, the lack of specificity of immunoassays and the extra renal sources of NGAL can generate difficulties in evaluating NGAL basal values and in establishing diagnostic cut-offs. Moreover, the optimal measurement unit to report NGAL values is still controversial. The aim of this study was to measure urinary NGAL in a population with preserved renal function in order to evaluate the reference interval, expressing results as both mass concentration (μg/L) and ratio to urinary creatinine (μg/g). 170 apparently healthy subjects (90 men and 80 women, ranging from 31 to 80 years) with normal renal function were enrolled in the study. NGAL was measured in the second morning void urinary sample by Abbott reagents on Architect analyzer; creatinine was assayed by enzymatic method on Roche Cobas C311. The distribution of NGAL values in the population was highly asymmetric, either expressed as mass concentration (median, 19.7 μg/L; 95th percentile upper reference limit ,106.7 μg/L) or normalized to creatinine (median, 22.0 μg/g; 95th percentile upper reference limit,160.5 μg/g). When expressed as ratio to creatinine, NGAL values were higher in females than in males (median, 28.2 vs. 21.4 μg/g; 95th percentile upper reference limit, 199.7 vs. 169.5 μg/g), due to lower urinary creatinine concentrations in females.

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