Determining the origin of hematuria by immunocytochemical staining of erythrocytes in urine for Tamm-Horsfall protein

Purpose: We analyzed the feasibility of immunocytochemical staining of urinary erythrocytes for Tamm-Horsfall protein to differentiate renal from nonrenal hematuria. Materials and Methods: Urine samples collected from 74 patients with hematuria were evaluated. Erythrocytes in urine were inspected morphologically and the same samples were immunocytochemically stained with antibody against human Tamm-Horsfall protein. Results: Erythrocytes in urine were clearly stained for Tamm-Horsfall protein in renal hematuria. Tamm-Horsfall protein immunocytochemistry was more consistent with clinical diagnosis than morphology. Conclusions: Immunocytochemical staining of urine erythrocytes for Tamm-Horsfall protein appears to be a reliable tool to differentiate renal from nonrenal hematuria.