"He said 'I know what's wrong with you' and went across the room and pulled out a huge rolled up file - it was our family tree.
"That's how we found out more about this condition - he was actually studying our family."
The consultant told her to make the most of her life, because it was never going to be the same, and Ms Patterson rang her brother and told him to get checked out.
That was a little over 16 years ago and Mr Patterson had been feeling tired, but put it down to working 60 hours a week.
He got in touch with his doctor and ended up discovering he was running on only five per cent kidney function.
"That was in May - by December I was on dialysis three days a week.
"I got on the transplant list and followed the doctor's advice about looking after myself - I was determined to do what I was told to do."
Sixteen years ago, he got the call that a kidney was available and was rushed to Wellington Hospital for the operation.
Apart from one rejection episode that resulted in a three-week stint in hospital, it was a success.
Ms Patterson endured five years of dialysis, a gruelling regime accompanied by severe migraines, during which time a friend offered to be a donor.
It took two years to get through all the hurdles, but then 12 years ago, she too had the transplant.
Both said the transformation in their wellbeing was almost immediate after their operations.
"For me the big thing has been the self-worth I have gained," said Mr Patterson.
"Dialysis is such a debilitating process - you lose all your sense of self-worth and feel you are a burden on society and your family.
"It was only my determination and Christian faith that gave me the hope to get through."
Since his transplant he had focused on giving back, including volunteering at the Art Deco shop in Napier, acting as an Art Deco guide, and more recently he began a volunteer chaplaincy assistant training course at Hawke's Bay Hospital.
Ms Patterson returned to full-time work after her transplant, but with an average life-span of seven years for transplanted kidneys, the siblings know they are on borrowed time.
They have both since developed Type 2 diabetes as a result of the drug regime and Mr Patterson had also been treated for skin cancer, another side effect of the drugs.
"Any day we could go into renal failure - that hangs over your head but you cant let it rule your life, you can't live in fear," Ms Patterson said.
For those waiting on transplant lists, Mr Patterson advised keeping a positive attitude, and staying in the best possible health so if a kidney came up they would be ready for an operation.
What was needed, however, was more donors - both living and deceased.
Currently there were more people waiting for a kidney on the deceased donor list (over 400 people) than there were available kidneys.
Mr Patterson said a big problem was that people would list themselves as a donor on their driver's licence, but family would overturn this after they died.
"There really needs to be some change of legislation to prevent this."
Ms Patterson stressed that anybody could offer their services as a live donor, and they did not have to know the recipient.
"If by telling our story we could inspire just one person to consider being a donor that would be great."