A New Diagnostic Immunoassay for Proximal Tubule Injury

Adenosine deaminase binding protein (AdAbp), a glycoprotein found in the epithelial cells of the brush border of the proximal tubule, is shed into urine following kidney damage. A sandwich enzyme immunoassay is described that uses two monoclonal antibodies, URO-4 (S27) and URO-4a (S23), which react with different epitopes on AdAbp (2, 24). Release of AdAbp into the urine appears to reflect the severity of the insult to the nephron and its measurement may assist in distinguishing between tubular disease and glomerular disease and may be useful in indicating renal toxicity.