Urinary Podocyte Count as a Potential Routine Laboratory Test for Glomerular Disease: A Novel Method Using Liquid-Based Cytology and Immunoenzyme Staining

Abstract

Introduction: This study investigated whether our urinary podocyte detection method using podocalyxin (PDX) and Wilms tumor 1 (WT1) immunoenzyme staining combined with liquid-based cytology can serve as a noninvasive routine laboratory test for glomerular disease. Methods: The presence of PDX- and WT1-positive cells was investigated in 79 patients with glomerular disease and 51 patients with nonglomerular disease. Results: The frequencies and numbers of PDX- and WT1-positive cells were significantly higher in the glomerular disease group than in the nonglomerular disease group. The best cutoffs for PDX- and WT1-positive cell counts for identifying patients with glomerular disease were 3.5 (sensitivity = 67.1% and specificity = 100%) and 1.2 cells/10 mL (sensitivity = 43.0% and specificity = 100%), respectively. Conclusion: Because our urinary podocyte detection method using PDX immunoenzyme staining can be standardized and it detected glomerular disease with high accuracy, it can likely serve as a noninvasive routine laboratory test for various glomerular diseases.