[3] He established the Tissue Type Laboratory at Oslo University Hospital in 1970, which later became the Department of Transplant Immunology.
He studied the genetic origin of the indigenous people on Easter Island.
The collection of genetic material from Native American peoples was dated to the period 1280–1495, long before the arrival of Europeans on the island in 1722.
[5][6] In 2004, the king appointed Thorsby a commander of the Order of St. Olav "for his research efforts in transplant immunology.
[3] Thorsby was elected a member of the Norwegian Academy of Science and Letters in 1992.