
Forensic scientists in Birmingham, who carried out the tests, have been looking for evidence of the four-year-old's blood, saliva and hair. They have also been looking for evidence of other people who could be linked to the investigation.
Sky's Martin Brunt said: "It could identify new suspects, it could affect the status of the only suspect in the case, Robert Murat. It could explain something of what happened on the night she disappeared - or the tests could be inconclusive, which could lead to the winding down of the investigation."
He said that the fact that the apartment had been re-let after Madeleine's disappearance meant that finding relevant forensic information had always been considered a "difficult task" as it could have been contaminated by people staying there. Portuguese police are not commenting on the results.
Brunt said the McCanns had not been officially told that the results had been handed over to the Portuguese police. But he said both the family and the McCanns have invested the forensic tests with a great deal of importance, and that detectives were expected to have a meeting with the family about the results.
The only person named as a suspect so far is British expat Robert Murat, who lives near the apartment the family was staying in at the time. He insists that he had nothing to do with Madeleine's disappearance.