Our reasoning in glomerular pathology relies on measures of the composition and amount of proteinuria, and the presence of red blood cells (RBCs) in the urine. In the case of isolated hematuria, the question of the origin of RBCs arises. In 1973, Brod was the first to provide some morphologic clue: “red cells of glomerular origin generally bear traces of their long journey [in] the renal tubules.”1 But it was Birch and Fairley who, in 1979, described these changes under phase-contrast