Research samples collected over decades at a Swedish medical university were destroyed when a freezer malfunctioned during the Christmas holidays, the institute said.
The samples were stored in tanks cooled with liquid nitrogen, at a temperature of -190C, at Karolinska Institutet (KI) in Stockholm.
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Sometime between December 22 and 23, there was an interruption in the supply of liquid nitrogen to 16 cryogenic tanks, and while the tanks can go without additional liquid nitrogen for four days, they were left without it for five, resulting in the destruction of samples from various institutions.
Matti Sällberg, dean of KI’s southern campus, said on Monday: “It happened at possibly the absolute worst time imaginable in Swedenjust one day before Christmas Eve.”
The incident has been reported to the police, the university added.
Some media reported that the estimated value of the lost specimens was around 500 million kroner (£37 million).
Sällberg said no official estimate of the value of the samples lost had been made, but said it was easily in the millions.
“Those most affected are those who research leukemia, they have collected samples from patients over as many as 30 years,” he added.
An internal investigation was launched at the university and despite no indication of sabotage, the incident was also reported to the police.
Sällberg said: “There is currently no indication that it was due to outside influence, but the police report was done to cover all bases.”
The samples were all strictly for research, so they would not affect the care of any current patients, but were intended to be used in future research.
“These are samples that have been the subject of extensive studies and there were plans for more studies,” said Sällberg.