WINNIPEG -- For most of us, our blood falls within the four major types.

In the case of an emergency, you would be given a blood donation from another person whose blood is compatible, but in some cases, a person’s blood can contain antibodies which trigger immune reactions against other blood types -- reactions which can be fatal.

This is why Canadian Blood Services has a lab dedicated to testing blood compatibility and storing rare blood for patients in need -- patients like Stephen Ash-Hamon, who was diagnosed with leukemia and required an emergency blood transfusion in June of 2018. 

“They don’t see blood like mine every day,” said Ash-Hamon.

Dr. Don Houston said Ash-Hamon, 70, was incompatible with his own blood. 

“His own immune system was attacking his own red blood cells,” said Houston. 

“If we find a patient has an antibody, we go across the hall to our antibody room.”

In the specialty lab, known as a cross lab, blood technologists test against more than 300 blood group antigens people can react against. It’s also where rare blood is stored in cases of emergency. 

Ash-Hamon credits this lab for saving his life. 

“If I didn’t get those blood transfusions, I don’t know if I’d be sitting here,” he said. 

--With files from CTV’s Maralee Caruso