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Urinary NGAL levels may aid in diagnosing kidney impairment in cirrhotic patients

Neutrophil gelatinase-associated lipocalin may be a useful biomarker for differential diagnosis of impaired kidney function among patients with cirrhosis, according to recent study results.

Researchers evaluated the urinary levels of neutrophil gelatinase-associated lipocalin (uNGAL) in 241 patients with cirrhosis. This cohort included 72 participants without ascites, 84 with impaired kidney function, and 85 with ascites but without impaired kidney function. The group with impaired kidneys was further divided into those with pre-renal azotemia related to volume depletion, chronic kidney disease (CKD), hepatorenal syndrome (HRS) or acute tubular necrosis (ATN).

Patients with impaired kidney function had greater uNGAL levels than the other groups (74 mcg/g creatinine vs. 40 mcg/g in those with ascites and 31 mcg/g in those without ascites, P<.0001 for both comparisons). In the group with impaired kidney function, uNGAL values were higher among those with ATN (median 417 mcg/g creatinine) compared with participants with pre-renal azotemia (30 mcg/g), CKD (82 mcg/g) and HRS (76 mcg/g) (P=.0006). The median level among HRS patients was significantly different from that of the azotemia patients (P=.0029) and the ATN patients (P=.0038), but not the CKD patients (P=.39).

Participants with urinary tract infections (n=25) had greater uNGAL levels than those who did not (N=216) (median 166 mcg/g creatinine vs. 42 mcg/g, P<.0001). Patients with other types of infections (n=64) had higher levels than those without infections (n=152), but this difference was not statistically significant.

Patients with HRS were further divided according to type, including those with classical type 1, classical type 2, and HRS associated with infection. Participants with type 1 had higher uNGAL levels than patients with type 2 (147 mcg/g creatinine vs. 43 mcg/g, P=.0041), and patients with type 1 and those with infection-associated HRS had higher values than those with pre-renal azotemia (P=.0026 and P=.0123, respectively).

“If these results are confirmed in further studies, uNGAL levels may be useful in the differential diagnosis of impairment of kidney function in cirrhosis,” the researchers wrote. “When using this kidney biomarker, urinary tract infections should be ruled out because they may increase uNGAL levels.”