The BBC's Richard Hannaford: "Laboratory errors accounted for 41 cases"

In 1996-97 there were 81 such cases. In 1997-98 this rose to 110, including two cases which led to the death of patients.

Overall, including cases where patients received infected blood, there were 197 problematic incidents - nine of which resulted in death.

A blood standards group is calling on the government to fund improved procedures to ensure patients receiving transfusions get the right type of blood.

Identifying patients' blood type

The Serious Hazards of Transfusion group, which is affiliated to the Royal College of Pathologists, published the report.

Blood is needed for many operations

It calls on the government to pay for the evaluation and development of computerised blood control systems.

It also wants patients to be issued with a unique identity number to prevent them receiving the wrong type of blood.

The report recommends steps hospitals can take to improve procedures and safety.

Laboratory errors accounted for 41 of the incidents, including one of the fatalities, according to the group.

The BBC's Health Correspondent Richard Hannaford: "The report says a new system is needed"

Failings in bedside checks accounted for another 46 mistakes, including the second death.

The total of 197 incidents was up from 169 the previous year.

'Transfusion is safe'

Dr Lorna Williamson, a transfusion specialist at Cambridge University, is one of the report's authors. She also works for the National Blood Service.

Dr Lorna Williamson puts the figures in perspective

She told BBC News Online blood was still "extremely safe" as there were more than 3.5 million blood components transfused last year and only 197 reports of problems.

But she said: "We do want to make some recommendations to improve the safety of blood.

"One of the things we are still seeing is blood intended for one patient being given to another patient because of failure to identify patient and blood correctly."

She said there was a need, in the short term, to improve staff training. But in the long term the focus should be on hospitals computerising records.

Barcode tracking system

Blood is given a barcode when it is collected, and this provides the National Blood Service with a means of tracking it through the system.

Donated blood is tracked by barcode

But blood products are only tracked in this way until they reach the hospitals where they are required.

Dr Williamson said the system could be extended to hospitals in the future to prevent mistakes by nurses and doctors.

She said: "The most comprehensive way to operate the system would be to have a barcode on the patient's wristband. It would also go on any samples taken from the patient.

"It would track that blood through the whole laboratory system as well, so that system would have other benefits."