Sam Ryan's blood is special.
After a near-death experience when he was 17, he required a transfusion of 22 units of blood and plasma.
But the terrible accident had an unlikely upside — he developed an extremely rare antibody that saves the lives of thousands of babies every year.
In 2017, Sam was driving to the regional NSW town of Forbes to work at the Vanfest music festival.
After falling into a microsleep, he went hurtling off the road and into a tree at 100 kilometres per hour.
Sam arrived at Sydney's Westmead Hospital by emergency helicopter with a broken pelvis, leg and foot.
"The injuries were bad, bad enough that when I got to the hospital, when I was alive, it became a limb salvage operation," he said.
"And luckily I've still got my leg."
He required so much blood that the helicopter flight had to make a detour to pick up more.
"The only reason I made it there was because of the blood that was given to me in the helicopter," he said.
"I'm under no illusion that if it wasn't for that, and if that rescue helicopter wasn't available, I would not be here today."
Now 22, Sam celebrated his miraculous rescue with a series of tattoos, one of which depicts the helicopter that saved his life on the back of his left leg.
Granted a second chance at life, Sam said he now takes every new day as it comes.
"Every day's a day I shouldn't have had," he said.
"I'm trying to make the most of it and do exciting things and make the best of every opportunity I've got."
What is Anti-D blood and how does it save babies' lives?
The Anti-D antibody can only exist in the Rh (D) negative blood type.
Pregnant women who have Rh (D) negative blood but carry Rh (D) positive babies can develop Rhesus disease if the baby's blood enters the mother's bloodstream.
If this happens the mother's body produces antibodies that can destroy a baby's red blood cells.
Once that baby is born, the mother's next pregnancy could result in an Rh (D) positive baby being attacked by the mother's antibodies.
The Australian Red Cross Lifeblood said 17 per cent of pregnant women received the Anti-D injection around 28 weeks and 36 weeks gestation, accounting for tens of thousands of births a year.
Injections prevent the potentially fatal haemolytic disease of the fetus and newborn, a severe type of anaemia.
The treatment was pioneered in Australia in 1967 and has since distributed millions of vaccines across the country.
When Sam received his many blood transfusions in the emergency helicopter, he said one of the donors must have had the D antigen in their blood.
After the transfusions, Sam's body now produces the Anti-D antibody independently.
Only around 100 Australians donate the antibody regularly, according to the Red Cross, making it extraordinarily rare.
Australian Red Cross Lifeblood even runs an Anti-D program, which takes donors without the antibody and gives them an infusion of D positive blood so they start producing the antibody themselves.
Program participants require ongoing D positive infusions to continuously produce the antibody.
Bloody lucky to be alive
Sam Ryan said the antibodies flowing through his veins were a gift he was grateful to share.
"Knowing something good came out of the blood transfusion I was given, it feels good to be able to give something back because there's not enough, clearly," he said.
"That I'm saving babies' lives, I mean, it's a bit more special."
After barely escaping death, he said his perspective on life had changed forever.
"Knowing that it could have all been over very quickly … in the big picture, things that worried me before, don't."
