Proteinuria typing: how, why and for whom?

The typing of proteinuria is one of the complementary examinations carried out during the exploration of proteinuria. It aims to separate and identify the different proteins, or fractions of proteins, that make up proteinuria. The nature and relative importance of the proteins present reflect the location of the renal involvement and help to determine the etiology. The typing of a proteinuria also allows the detection of a monoclonal component in urine and its quantification. Finally, it allows highlighting the existence of a proteinuria of overload that can occur in the absence of kidney damage. Many methods allow the typing of proteinuria, and these have benefited in recent years from technological advances. The purpose of this review is to summarize typing methods currently used, their benefits and limitations, and the help that these diagnostic tools can provide to the management of patients.