Over the last six and a half years, seven-year-old Jethro has received 673 bags of plasma to boost his red blood count.
Today he is being given 570ml in two bags, over five hours.
Jethro has haemolitic uramic syndrome, the breakdown of red blood cells causing renal failure, micro clotting to the major organs, risk of heart attack, stroke and potentially death.
Dr Ranford Addo says plasma for Jethro is lifesaving.
"In the sense that he doesn't make an important component of the plasma by himself. He is one of just a handful of patients in the country with this condition."
Plasma differs from donating whole blood, in that the donor's red blood cells and plasma are separated, with the red cells channelled back to the donor.
"[Jethro] has a good sense of humour, and that is important when you have a chronic condition like he does," Dr Addo said.
But at any time, Jethro could develop an immunity to the plasma, leaving him vulnerable to kidney failure and a host of other life-threatening conditions.
In the long-term the family need Soliris, a drug that costs about $500,000 a year and is not currently funded in New Zealand.