The Lachine Hospital in Montreal is testing patients who underwent bariatric surgery between 2012 and 2014 for possible HIV or hepatitis infection, after a review found a tool used in the procedure hadn't been thoroughly cleaned.

About 150 people received letters last February informing them they should undergo tests as a precaution.

The McGill University Health Centre's medical director of infection prevention, Dr. Charles Frenette, told CBC News that 89 per cent of the patients have responded to the notices, and all have tested negative.

The hospital is trying to track down the remaining 11 per cent of patients by letter and by phone to ensure they get tested.

Frenette said a routine review of cleaning and sterilization procedures found that the tool hadn’t been completely disassembled during past cleanings.

The tool — a liver retractor — is used to lift the liver to allow the surgeon a better view of the stomach.

Frenette said surgical debris was discovered in a connection point that hadn’t been unscrewed.

“It might have been old dust. It could have been old blood, which is why we recalled all the patients,” he said.

The risk of infection was minimal, said Frenette.

“But in circumstances like that, we take no chances and do a recall,” he said.

Health Canada and Montreal’s public health agency have also been notified of the problem to ensure other hospitals are made aware of the proper cleaning procedure for the tool.

Bariatric surgery encompasses a range of surgical procedures that help with weight loss.

Patient protection group slams recall procedure

Paul Brunet, chair of the Council for Patient Protection, criticized the use of letters to notify patients of the recall.

He said it's important that patients be notified by phone, so they can ask questions and be given more information.

"This is not a car recall. You don’t send a letter to patients — you call them," he said. "It doesn’t cost a lot to talk to someone. You made a mistake — don’t have the patients suffer more by getting a letter in the mail."

Brunet said lawsuits are possible in such circumstances.

"If patients can prove that there was a specific and direct impact on their health, yes [monetary compensation is possible]. Sometimes stress and anxiety can cause a lot of damage to your health," he said.