Australia's distribution of blood types is changing and it is most likely based on the genetic diversity of migrants, according to new research.
A landmark study released on Monday in the Medical Journal of Australia has revealed a higher rate of positive blood types among Australian patients and first-time blood donors.
The study used data from 1.3 million people across Australia and 500,000 blood donors, using patient data for the first time in determining Australians' blood types, as opposed to only blood donor data.
Australian Red Cross Lifeblood lead researcher Rena Hirani found that positive blood types have become more prevalent - and she says the country's shifting immigration patterns is driving the change.
Rena Hirani is the lead researcher at Australian Red Cross Lifeblood. Credit: Supplied / Australian Red Cross Lifeblood
Compatible blood types are important in safe blood transfusions to prevent outcomes like kidney failure and the immune system rejecting the transfusion.
The most common antigens on the red blood cells are A and B, which can also appear together as AB, or not at all in the O type. The blood types can also be further identified as positive or negative - what is known as the Rhesus factor (RhD).
Dr Hirani found that Australians with blood group AB positive doubled from two to four per cent, and B positive rose by a third from eight per cent to 12 per cent.
"Blood groups - just like your hair, skin and eye colour - are determined by genetic background," Dr Hirani told SBS News.
"What we know is that in the last 10 years, we've had high migration from places like southeast Asia, China, and India; and in these places, group B and AB is a very common blood group.
"Alongside that, C is actually hugely common in those particular ethnic backgrounds as well."
Dr Hirani said that the positive blood types of migrants - who make up almost one-third of Australia's total population - reflect the change in blood type patterns she has found in her research.
Based on data that was retrieved in the 1990s, it was thought 19 per cent of Australians had a negative blood type - and of that group 9 per cent were O negative.
During the COVID-19 pandemic, in Australia. Around 12,000 donations are needed monthly of all blood types, with the O negative blood type in particular in high demand.
But now it is understood that 14 per cent of Australians have a negative blood type and 6.5 per cent are O negative.
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Understanding the shift in common blood types is crucial to know what blood donations hospitals should be requesting, and to know the true scarcity of O negative blood, Dr Hirani said.
"A lot of hospitals are relying on O negative blood for emergency purposes, but with this information, we can show that it's going to become increasingly challenging to collect."
She said the research points to a potential pivot for hospitals in the future that may seek a bigger supply of positive blood types.
"There may be an alternative option of using O positive blood groups more frequently in emergencies, which is really exciting," she said.
"We are working with community groups to ensure that our blood donors diversify ... because it's really important to make sure that we have a blood type that matches the right patient at the right time."
The O negative blood type is considered the universal blood donor type because it can be donated to any other blood group with the least risk of an adverse reaction. This is because the red blood cells do not carry antigens that could react negatively to other blood types.
Australian Red Cross Lifeblood conducts blood donations through bookings made on its website lifeblood.com.au, hotline 13 14 95 and DonateBlood app.
