“In Vitro Biopsy”: With Good Reason

Many thanks for the impressive and detailed treatment of the problem of early detection of kidney disease (1). The topic is not only important for children and young adults but also for patients of a more advanced life age. Without wanting to cite relevant scientific studies I wish to point out explicitly and on the basis of my own experience the importance of microscopic analysis or the urine sediment of the second fresh morning urine sample—not without reason is this investigation known as “in vitro biopsy.” It is preferable to do the microscopy oneself, rather than trust in apparative technology-based findings—and not only when in doubt. The complete morphological spectrum of glomerular erythrocytes should be considered, rather than only the acanthocyte count. The diagnostic benefit/utility of this approach has been confirmed in our hospital in the diagnosis of kidney disease of any cause. There is nothing to add to the subject of proteinuria and differentiation of the individual protein fractions in urine.