NHS Tayside had to rush in emergency blood supplies after a lightning strike knocked out power to Ninewells Hospital.
The hospital lost power following a lightning strike on Saturday which affected the blood supplies held by the Scottish National Blood Transfusion Service in the Dundee hospital.
Blood can be kept for between 28 and 49 days if stored between 2C and 6C.
Because the blood does not contain any white blood cells it is at risk of bacterial infection if not kept below room temperature.
However, it is understood the power cut knocked out the unit’s refrigerators and the decision was taken to dispose of the blood rather than risk contamination.
Lochee Labour councillor Charlie Malone said he was concerned that the hospital had been so affected by Saturday’s freak weather and believed there should be better back up systems in place, particularly for IT.
The storm, which caused flash floods across Tayside and Fife, also knocked out the phone and IT systems at the hospital.
NHS Tayside said on Sunday power had been “restored quickly” to all areas and engineers had repaired the IT and phone systems on Sunday morning.
Medical staff resorted to using their mobile phones while dozens of outpatients had MRI scans cancelled on Sunday because data could not be transmitted electronically.
Mr Malone said: “I was told they couldn’t use the blood they had for transfusions so they had to get more sent through from Perth.
“That was the most serious problem.
“There should be better contingency plans in place.”
A spokesperson for NHS Tayside said: “There was a brief power outage at Ninewells Hospital on Saturday as a result of a lightning strike.
“The Scottish National Blood Transfusion Service (SNBTS) donor centre based at Ninewells was affected by this power outage.
“SNBTS follows UK Blood Safety and Quality Regulations which include strict guidelines for the safe storage of blood and disposed of its stock in line with these regulations.
“The stock was fully replenished by SNBTS later the same day.”
An SNBTS spokeswoman said there had been “no problems” with replenishment on Saturday evening.
In February it was revealed Ninewells Hospital needs a £12 million upgrade to its electricity supply.
A “short term” power outage had showed many clinical areas of the hospital did not have adequate generator back up.
The health board said it is making upgrading its infrastructure “a priority” and had submitted a business case to the Scottish Government.
Dundee-based Labour MSP Jenny Marra has said it is time a replacement for Ninewells is now built.
She said: “This is extremely worrying. The key thing is to prevent contamination so it is obviously best the samples are destroyed.
“However, this is another indication the Ninewells facility is not as fit for modern purpose as we would like.
“I would hope the Scottish Government now considers the need to renew the acute hospital in Dundee.”