A body fluid stain contained 180 megabecquerels per liter of the radioactive isotope, while a typical sample would contain 5 megabecquerels per liter, Bochud said. A becquerel is a unit of measurement of radioactivity.
The fabric of Arafat's clothing, without body fluid, contained less than 10 megabecquerels per liter, Bochud said.
Tests involving biological samples -- such as urine, sweat or blood -- contained higher levels than other samples taken from his clothing, he said.
Arafat's widow had left his clothes inside a sports bag from the time they were returned to her eight years ago from the hospital, Bochud said.
It was not clear whether anything that may have happened to the clothes -- over the years or in the testing process -- may have affected the test results.
Asked whether polonium-210 could have been applied to the items since Arafat's death, Bochud said, "Anything is possible."
Bochud also said the Institut de Radiophysique did not verify that the clothing was Arafat's; another organization concluded that the DNA on the items was similar to that of Arafat's daughter.
Zahwa Arafat provided her DNA for the comparison, Suha Arafat told CNN. The wait for test results, which lasted months, "was emotionally difficult," she said.
Former Russian spy Alexander Litvinenko died of polonium poisoning in London in 2006.
But it's hard to compare the cases of Arafat and Litvinenko, who was diagnosed when he was alive, Bochud said.
Arafat's symptoms when he died were not entirely consistent with polonium poisoning, he said.
"For example, the bone marrow stayed in good shape until (the) death of Arafat. In other cases of polonium poisoning there is a decaying of the bone marrow," the medical expert said. "Another point, he did not lose his hair as would be expected in the case of polonium." poisoning.
Scientists performed more than 50 measurements on the belongings between February and June, he said.