The kidneys are a target organ of COVID-19 and are affected very early in the course. However, this is precisely where there is strong prognostic potential: As early as last spring, COVID-19-associated nephritis was identified as an early warning signal for severe courses of the infectious disease and studies to that effect were published. In that regard, the research group led by Professor Oliver Gross, Department of Nephrology and Rheumatology at Göttingen University Medical Center (UMG), screened 223 patients in a study and included 145 of them as a predictive cohort. Study endpoints were ICU admission or mortality. As a result, early urinary changes that are easily detectable using test strips indicated a more severe COVID-19 course. When combined as a predictive system (urine and serum markers), it was possible to predict outcomes. “This means that kidney values are a seismograph for the course of COVID-19 disease,” explained Prof. Gross, the head of the study, at the Opening Press Conference of the 2021 ERA-EDTA Congress.