In the study by Siew et al, over 400 critically ill patients underwent urinary NGAL measurement within 24 hours of admission to an ICU; these patients were then followed prospectively and assessed for AKI, as defined by an increase in serum creatinine of greater than 0.3mg/dL or a greater than 50% increase in the baseline creatinine. The investigators found that elevated urinary NGAL levels was moderately successful in predicting AKI.
In the second study by Paragas et al, investigators looked at the ability of urinary NGAL to distinguish between HIV patients with a collapsing FSGS pathology (e.g., "HIVAN") compared to HIV patients that had either normal kidney function or CKD from another cause. Importantly, patients with HIVAN had 11-fold higher urinary NGAL levels compared to HIV-positive controls without a reduced GFR, and still 5.5-fold higher urinary NGAL levels compared to HIV-positive controls with CKD due to a cause other than HIVAN. These findings may prove useful in terms of diagnosing patients with HIV and rapidly declining renal function with HIVAN in a non-invasive manner (e.g., no biopsy). While biopsy should still likely remain the gold standard until these findings can be confirmed with a larger n, it could potentially be useful information in patients where biopsy is deemed too risky to proceed--a situation in which HIVAN patients may commonly find themselves.