Significance of urinary liver-type fatty acid-binding protein in patients with normal renal function after undergoing intestinal urinary diversion: a preliminary study

Background Liver-type fatty acid-binding protein (L-FABP) in urine is one of the early diagnostic biomarkers for acute and chronic kidney injuries. Although this protein is also identified in the intestine, there is no verified reference value for patients with intestinal urinary diversion (UD). The aim of the present study was to measure L-FABP values in such patients and compare them with the results for patients without UD. Methods Spot urine specimens were collected from 41 patients with UD and 50 subjects without UD with estimated glomerular filtration rates of over 60 ml/min/1.73 m 2 , and the L-FABP values were measured. The normal upper cutoff value in healthy subjects without UD is considered to be 7.24 μg/g Cr. First, the median values of the two groups were compared. Next, the subjects with negative proteinuria and without comorbidities associated with renal function were further selected and the median values of the groups were compared. Results The mean age was significantly higher in the UD group. The types of UD were ileal conduit (38 patients) and ileal neobladder (three patients). The median L-FABP value in the UD group was significantly higher than that in the non-diversion group (89.1 μg/g Cr vs. 2.0 μg/g Cr, p < 0.0001). After adjustment for their backgrounds, the median value remained higher in the UD group. Conclusions L-FABP values in subjects with UD are higher than in those without UD. By this result, to develop a reference value in patients with intestinal UD population, further studies are required.