The integrity of Canada's blood supply once again appears to be in question after a federal report uncovered thousands of "high-severity" errors in the transfusion system that potentially could cause serious harm to patients, the National Post reported.

The Post, which obtained the Public Health Agency of Canada pilot study of 11 hospitals under the Access To Information Act, said the report also warns of a "staggering" cost to the system because of wasted blood.

It said many of the mistakes involved mislabeled blood samples taken from patients for testing, which creates a risk they may get the wrong type of blood.

"Errors came with a considerable patient and financial burden," says the report, according to the Post.

More than 6,000 patients had to have samples re-taken and their transfusion delayed because of mix-ups, while nearly $800,000 worth of blood products were destroyed.

"Given that the participating hospitals transfused less than 10 per cent of blood products nationally, the total Canadian burden is considerable," the report says.

Agency officials played down any real danger, telling the Post that most of the mistakes were "near misses" that were spotted before any harm was done.

But the report raises the spectre of the tainted-blood scandal of the 1980s, when thousands of Canadians were infected with HIV and hepatitis C due mainly to poor donor-screening practices and other problems with the system then run by the Canadian Red Cross Society.

The disaster led to the creation of Canadian Blood Services, an independent agency now responsible for the blood supply.

Despite the adverse report, Canada's blood-transfusion system remains one of the safest area of medicine because of the reforms that grew out of the scandal, Dr. Jeannie Callum, director of transfusion medicine at Toronto's Sunnybrook Health Sciences Centre, told the Post.

Sunnybrook, for instance, has stepped up safety by bar-coding samples to match a patient's bar code to reduce chances of a mistake and training medical residents in a "transfusion camp."

It's especially important not to waste blood products, said Callum, who works in the Public Health Safety Agency's blood surveillance program. The agency's report analyzed results from the system's first three years of operation, 2005-2007.

It identified 31,989 errors, just under 3,000 of them rated at high severity that could potentially harm patients.
The report said 23 patients were actually harmed, suffering allergic reactions or fevers after receiving the wrong blood type or product, the Post said. There were no deaths, which Callum said are rare.

"Canada has one of the safest blood systems in the world," agency spokeswoman Sylwia Gomes told the Post via email, adding the surveillance program has been expanded to 15 hospitals.

"The large majority of reported errors in the blood handling and transfusion process were minor and presented no risk of an adverse event to the patients involved."