Once it has been fully tested and produced commercially, the test could enable transplant recipients around the world to test their own kidney function daily at home, eliminating the need for expensive and invasive kidney biopsies.
After seven years of work, scientists had been able to devise a test to identify a molecule called major histocompatibility complex (MHC) molecules produced in the urine of transplant recipients whose new kidney was failing, study co-ordinator Dr Alex McLellan, of the Otago's department of microbiology and immunology, said yesterday.
A study analysing urine samples from 103 recipients from New Zealand, Australia and Switzerland showed patients with the MHC molecule in their urine had a 90% chance of their kidney failing, he said.
The test, which he said would cost "a few cents" to carry out, would enable recipients and doctors to discover much more quickly if a kidney was failing and start a course of additional immunosuppressive drugs to counter that.
The researchers' findings were published this month in the international journal Transplantation.
Dr McLellan said he expected it would be another five to 10 years before test kits were on the market.
Before then, more intensive clinical trials were required.
"We are hoping the next round of trials will involve more than 1000 people, probably in the US where where are a much larger number of transplant recipients."
The university was also seeking a commercialisation partner - a company which would assist with producing test kits for sale.
With chronic kidney disease a worldwide problem, the Otago research was internationally significant, Kidney Health New Zealand medical director Prof Kelvin Lynn said yesterday.
"Kidney transplants are the best and most cost-effective method of treating chronic kidney disease, so anything which can be done to improve the outcome for recipients is good news."
Prof Lynn, of Christchurch, said.
In New Zealand, kidney biopsies cost $1000-$2000 each and were stressful on patients who had already been through years of dialysis and a transplant, he said.
"I hope the further clinical trials show a urine test . . . will be as good as a biopsy.
"If it does that and the clinical trials can be translated into clinical practice, it will be good for patients, for the health system and for the economy."
Kidney transplants
• Best and most cost-effective treatment for treating chronic kidney disease.
• More than 500 New Zealanders awaiting transplants.
• 122 people received a new kidney in 2008, 53 from deceased donors and 69 from live donors.
Source: Kidney Health New Zealand