Suzi Wallis' first experience with blood donation was at birth.
She and her twin sister were born seven weeks premature. The newborns had their own battle for survival, Wallis weigned just 1.7 kilograms and her sister 1.8kg, but it was their mother whose life was immediate peril.
Desperately unwell after the birth of her babies, she needed a blood transfusion, Wallis said.
"She was given four pints (1.8 litres) of blood to save her life."
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It worked. Her life was saved.
Seven years later, it was Wallis' turn to have her life saved by donated blood.
An injury at birth had damaged her hearing and it was decided her hearing would be improved by the removal of her adenoids and tonsils. It was a decision that almost ended Wallis' short life.
She haemorraged during the operation and needed a blood transfusion.
"When I woke up the doctors and nurses were all clapping," she told the Herald.
"I nearly died. That transfusion saved my life."
Wallis is speaking as part of a New Zealand blood service campaign to get 10,000 new blood donors. On Monday, several businesses removed the letters A and O from their logos to highlight the need for the two blood types.
The Herald is running stories this week speaking to donors and people who have been saved by blood transfusions.
Wallis, a 45-year-old Onehunga-based counsellor, now repays the favour after she was given blood. Dozens of times over.
Since the age of 20, she has donated between 600 and 800ml of her blood every six to nine months.
She wanted to start donating earlier, in high school, but did not meet the weight limit.
"I wasn't heavy enough, but that's never been a problem since."
Despite having "difficult veins", which made it challenging for the medical staff trying to draw blood, Wallis had donated blood all her adult life.
She doesn't know who had received her A negative blood - except on one occasion, when an urgent call was made for the blood type just before the needle went in.
It was needed for a baby, she said.
"They didn't even have the needle in, and this staff member was walking around saying 'I need A negative, I need A negative'."
She had heard that in Sweden donors received a text when their blood was being used, but New Zealand unfortunately did not have the same system, Wallis said.
Despite that, she would always give blood. Doing so was part of a her life, she said.
"I just want to give back and it's not hard ... once I knew that I'd saved a life I thought 'why the hell wouldn't you do this if you can?' But only four per cent of eligible people in New Zealand do it. That is so sad."
Visit the NZ Blood Service website for a list of donor sites and to see whether you are eligible.
It's understood a NZDF aircraft and multiple helicopters are involved.