The Italian academic who had lunch with Alexander Litvinenko on the day he is alleged to have been poisoned remains "well," the hospital treating him said.
In a statement, University College Hospital revealed the latest tests on Mario Scaramella were "normal."
He remains under close observation after testing positive for Polonium-210.
The Italian has claimed both he and Mr. Litvinenko were poisoned because of information the former Russian spy was passing to him.
In a statement issued through his lawyer he revealed Mr Litvinenko, 43, had been passing information to him for several months.
He said: 'I have reason to believe that my poisoning and that of Litvinenko's is connected to the information that for months the same Litvinenko was passing me."
On his poisoning, he said: ''The urine examinations found traces of polonium significantly lower that that which was used to kill Litvinenko.
"But they were still considered to be potentially lethal and therefore capable of killing me.''
On Saturday doctors at UCH - in central London - said there was no evidence of "radiation toxicity" in his system following preliminary tests.
Dozens of locations have been checked for radiation since Mr Litvinenko's death on November 23.
The include Arsenal Football Club's Emirates stadium in north London where a contact of Mr Litvinenko attended a Champions League match.
Ex-KGB agent Andrei Lugovoi is believed to have met him at the Millennium Hotel in Grosvenor Square on November 1.
That is the day he is thought to have been contaminated in a West End sushi bar.
The Health Protection Agency has stated there is "no risk to public health" at Arsenal's ground.
Just under 3,000 people have called the NHS Direct line following the public health alert.
A total of 170 have been investigated with 24 referred to a specialist outpatient clinic for radiological exposure assessment.
Urine samples on 67 of the people thought most likely to be at risk of polonium contamination have all come back negative.
The only positive sample so far is that of Mr Litvinenko's wife Marina, who is not expected to become ill.
Traces of the substance have been found in 12 separate places across London.
Three BA planes feared contaminated with radiation have been cleared to return to service.
Friends of Mr Litvinenko, a fierce critic of Russian president Vladimir Putin, say he was murdered by a secret service hit squad - a claim denied by the Kremlin. Also In UK News