A new noninvasive urine test can distinguish among different causes of acute kidney dysfunction after transplantation. The test, which is described in a study appearing in the Journal of the American Society of Nephrology, may allow patients to avoid invasive kidney biopsies when their transplanted organ is not functioning properly.
When creatinine levels are elevated in the blood of a kidney transplant recipient, it is an indication that the transplanted kidney is not functioning well. There are several reasons for transplant kidney dysfunction, and no current blood or urine test can reliably differentiate them. Because it is important to establish the exact reason for kidney dysfunction in order to determine the appropriate treatment, physicians typically perform a needle biopsy of the transplanted kidney.
Now, however, Thangamani Muthukumar, MD, and his colleagues have developed a urine test that measures the levels of several messenger RNAs (mRNAs) that are directly related to the disease processes that cause kidney dysfunction. The researchers measured absolute levels of mRNAs in 84 urine samples from kidney transplant recipients who had undergone needle biopsy of the transplanted kidney to determine the cause of acute kidney dysfunction.
“Using statistical methods we combined the mRNAs to yield a diagnostic signature,” explains Muthukumar. The researchers developed two signatures from cells found in the urine that could differentiate, in a two-step approach, the common causes of acute kidney dysfunction with high accuracy. “Our study shows that when the creatinine level is elevated in the blood of a kidney transplant recipient, use of our urine test would differentiate the common causes of kidney dysfunction that led to the elevation,” says Muthukumar. Read the study abstract.
