Use

Measurement of urinary retinol-binding protein (RBP) is useful in assessing proximal renal tubular injury or dysfunction. Under normal conditions, RBP is filtered but reabsorbed by proximal tubular cells; elevated urinary excretion indicates impaired tubular function. Elevated excretion rates can occur with tubular disease, toxicity (e.g., heavy metals or nephrotoxic drugs), or in glomerulopathies with concurrent tubular injury. A 24-hour urine collection is considered the gold standard over spot collections for accurate quantification of RBP excretion. ([mayocliniclabs.com](https://www.mayocliniclabs.com/test-catalog/overview/609449?utm_source=openai))