Hyposthenuria: Sandor Koranyi's concept of renal insufficiency

Around the turn of the 19th century, the Hungarian physiologist and clinician, Sandor Koranyi, started to use physicochemical methods to estimate renal function. In parallel with the deterioration of renal function, he found characteristic changes in the freezing point depression of urine, which he termed hyposthenuria. On the basis of these findings, he was the first to introduce the fu functional concept of renal insufficiency.