Diagnostic Value of Serum Neutrophil Gelatinase-Associated Lipocalin for Adrenal Insufficiency.

The adrenocorticotropic hormone (ACTH) stimulation test is the gold standard for confirming adrenal insufficiency (AI); however, its requirement for frequent blood draws and pharmacologic stimulation can be a barrier to early diagnosis. This study aims to evaluate the diagnostic value of serum neutrophil gelatinase-associated lipocalin (NGAL) as a novel biomarker for diagnosing AI. This prospective study was conducted at Chonnam National University Hwasun Hospital between June 2020 and November 2021. Patients with either pituitary tumors or a history of exogenous steroid use who underwent the rapid ACTH stimulation test were included in the analysis. A total of 75 patients suspected of having AI were analyzed, with 31 patients (41.3%) being diagnosed with AI. Serum NGAL levels were significantly higher in the secondary AI group with pituitary tumors compared to the non-AI group (92.2±33.6 ng/mL vs. 74.7±24.1 ng/mL, p=0.037). There was a negative correlation between serum NGAL levels and cortisol levels 60 minutes after ACTH administration in patients with pituitary tumors (r=-0.246, p=0.043). A positive correlation was found between serum NGAL and baseline serum creatinine levels in the secondary AI group with pituitary tumors (r=0.400, p=0.002). The Receiver operating characteristic curve analysis revealed that the area under the curve for secondary AI was 0.673, with an optimal cut-off value of 78.4 ng/mL, yielding a sensitivity of 60.0% and specificity of 59.4% (p=0.038). Serum NGAL may serve as a supportive diagnostic tool for secondary AI when confirmatory tests are not feasible.