"However extensive toxicology testing is yet to be carried out. This will take a number of weeks."
The toxicology tests are a routine part of the examination of a corpse.
An inquest into the death of Patarkatsishvili, who was the ex-Soviet republic's richest man, will open on Friday.
The Georgian, who had claimed there were plots to assassinate him, reportedly died from heart failure, although he was not believed to have been in poor health.
Police said late on Wednesday that that they had found no traces of radioactivity after forensics experts spent the day studying the scene at Patarkatsishvili's mansion.
The case had triggered memories of the death by radioactive poisoning of Kremlin opponent Alexander Litvinenko in 2006, which have severely affected diplomatic ties between London and Moscow.
Patarkatsishvili, 52, had been accused by the Georgian government of fomenting a coup in the ex-Soviet republic.
The case was handed to a major crime investigation team because of its high-profile nature, a Surrey police spokesman said.
Police are attempting to trace the Georgian's movements in the 48 hours before his death.
The businessman was a major force behind an opposition movement that took to the streets in the Georgian capital, Tbilisi, last November, prompting a violent police crackdown.