The tests, carried out in laboratories in Belgium, Germany and the U.K., were needed to justify Ukrainian legal requirements in the case of any prosecution.
The latest tests confirm the dioxin level in Yushchenko's blood was 1,000 times what is considered acceptable, said Oleksiy Bebel, spokesman for the General Prosecutor's Office.
Yushchenko fell severely ill last year during the presidential election campaign, and after treatment in Austria was diagnosed as having suffered massive dioxin poisoning. It knocked him off the campaign trail for weeks, and left his face severely pockmarked. The scars still remain more than a year later.
Ukrainian authorities have called it an assassination attempt. No-one has been charged, although Yushchenko says the investigation is continuing.
In September, former Security Service head Oleksandr Turchinov charged Yushchenko's poisoning hadn't been proven because the president kept putting off tests in Ukraine.
Under Ukrainian law, tests must be conducted in Ukraine, or be overseen by Ukrainian investigators to be considered valid, making necessary the new analyses. Local laboratories were incapable of conducting the examinations, so investigators asked foreign laboratories for help.
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