Hellen Altendorf has been granted 2 US patents while listed as an inventor at Testo Ag. The first was granted in 2017 and the most recent in January 2019. Hellen Altendorf ranks #1,709,992 of 4,157,543 US inventors in our database (top 41.1%). Patent records list Hellen Altendorf in Kirchzarten, DE.