CHICAGO (CBS) — The number of people waiting for an organ transplant continues to grow, with currently more than 120,000 people on the waiting for an organ transplant, and more people are added to the list each year.

Dr. John Friedewald, a transplant nephrologist and director of clinical research for Northwestern Medicine’s Comprehensive Transplant Center, said sometimes it takes years to find a matching kidney for patients who need it.

“The average waiting time for a kidney is five years now. Unfortunately only one in three people survive on dialysis. So we have a critical problem whereas when the waiting time for kidneys were a year or two that wasn’t a big of a problem but a lot of people don’t make it to the top of the waiting list, they die on the list waiting for a transplant,” he said.

The new Kidney Allocation System is a federal organ transplant policy put into place in December, and it’s designed to improve kidney transplant wait times. Longevity matching is where doctors try to match the longevity of the kidney with the longevity of the patient.

“What we wanted to happen is happening. When we look at extreme mismatches in age between donor and receipient we’re seeing fewer of those extreme mismatching, more than 15 years difference between donor and recipient so we’re better matching longevity with candidates with longevity with kidneys. We’re seeing better access to minority candidates by switching to dialysis based waiting time,” Friedewald said.

The new system also allows anyone who has been on dialysis to get on a transplant waiting list, and have their start date set to when they first started dialysis.

April is National Donate Life Month, which was started by Donate Life America in 2003 to help encourage Americans to register as organ and tissue donors, and to celebrate those that have saved lives through the gift of donation.

Friedewald was the chair of the United Network for Organ Sharing (UNOS) committee that developed the new kidney allocation system.