Urine test spots trouble after kidney transplant

WASHINGTON (Reuters) - A quick urine test can spot a serious complication in people who have had a kidney transplant, enabling doctors to take steps aimed at preventing kidney failure, researchers said on Thursday.

The test, described by researchers at the University of North Carolina, detects a viral condition called polyomavirus nephropathy that affects about to 2 to 4 percent of kidney transplant patients.

The researchers said any hospital with the right equipment would be able to perform the inexpensive test, but added that they may develop it commercially.

Until now, the only way to know if a person had the condition was by performing an invasive biopsy to retrieve and test kidney tissue -- which in some cases fails to find polyomavirus nephropathy even if it is there.

Transplant patients who get the condition may develop chronic kidney failure and need another transplant.

Many people are infected with a polyomavirus and suffer no harm, but in people like kidney transplant patients who take powerful drugs to suppress the immune system -- the body's natural defenses -- the virus can become dangerous.

About 18,000 kidney transplants are performed in the United States annually.

It is crucial to diagnose polyomavirus nephropathy as early as possible before it does a lot of damage.

When it is detected early, doctors might be able to stop it from causing extensive damage by lowering the immunosuppressant doses to let the immune system tackle the virus, or give the patient antiviral medication, the researchers said.

"You hope that this early intervention clears the virus, and that everything -- like a little cough -- goes away," Dr. Volker Nickeleit, one of the researchers in the study appearing in the Journal of the American Society Nephrology, said in a telephone interview.

Nickeleit's colleague at the University of North Carolina, Dr. Harsharan Singh, developed the test in which the patient's urine is checked for clusters of the virus.

Results from the test can be available in about three hours; the test costs less than $400 to do, and it could be performed with current laboratory equipment, the researchers said. Any hospital or laboratory with an electron microscope should be able to do it, Nickeleit said.

In the study involving 160 patients, the test accurately detected the condition in all those who had it, the researchers said.

(Editing by Maggie Fox and Vicki Allen)