Use

Measurement of urinary retinol‑binding protein (a low‑molecular‑weight protein) is a useful aid in diagnosis and monitoring of proximal tubular dysfunction. Normally, RBP is filtered and reabsorbed by proximal tubular cells; elevated excretion indicates injury or dysfunction of these cells. Elevated excretion may reflect tubular damage from renal tubulointerstitial nephritis, nephrotoxic exposures, or coexisting tubular injury in glomerulopathies or vasculopathies. For spot collections, RBP concentration is corrected by creatinine to account for urine concentration variability.