The Sudarium of Oviedo has become scientifically entangled with the Shroud of Turin over the past several decades, as researchers sympathetic to both relics' authenticity have compared bloodstain patterns, wound positions and reported blood type between the two cloths, arguing the similarities are close enough to suggest both wrapped the same body. Critics of this comparison note that the Sudarium bears no image at all, only bloodstains, which makes claims of precise positional correspondence with the Shroud's image considerably harder to test rigorously than proponents sometimes present them.
Radiocarbon testing conducted on the Sudarium in the 1990s produced a date considerably later than the first century, results that supporters of the relic's authenticity have argued reflect contamination from centuries of handling and repair rather than the cloth's true age, an explanation critics regard as an unfalsifiable way to dismiss any unwelcome scientific result. The cathedral itself permits continued research on the cloth while, consistent with its handling of comparable relics elsewhere in this atlas, presenting the Sudarium's significance as a matter of venerated tradition rather than a claim it treats as scientifically settled in either direction.