Role of β2-microglobulinuria and microalbuminuria in pediatric febrile urinary tract infection

Urinary beta-2-microglobulin (β2M) and microalbumin concentrations were analyzed in 61 pediatric patients with febrile urinary tract infection (UTI). The results were compared with those of technetium-99m-labeled dimercaptosuccinic acid (^99mTc-DMSA) single photon emission computed tomography (SPECT) imaging. Noninvasive evaluations were made to localize the site of the UTI. Increased urinary β2M/Creatinine (Cr) or microalbumin/Cr quotients were not associated with renal inflammation, as defined by a positive renal scan. Increased urinary microalbumin/Cr is associated with UTI in febrile patients regardless of the level of infection (scan status), and may be an informative indicator of UTI. When microalbumin/Cr was ≥0.03, its sensitivity and specificity to predict UTI in febrile patients, regardless of the site of the infection, were 95.65% and 51.79%, respectively, and its positive predictive value was 62.0%. On the other hand, urinary β2M/Cr (≥0.13) demonstrates a statistically significant correlation with the presentation ora high grade of vesicoureteral reflux (p=0.02). We suggest that a prompt renal imaging study is warranted when the urinary β2M/Cr ratio is high (≥0.13).