WASHINGTON — The Food and Drug Administration is investigating whether faulty disposable plastic tubing in dialysis machines is letting blood leak out, possibly exposing patients to others' blood.
One company, Nissho Nipro Corp. of Ayutthaya, Thailand, on May 7 recalled 154,000 sets of PVC tubing sold in the United States after a Tucson, Ariz., hospital discovered problems.
Investigators with the FDA, Nissho and St. Mary's Hospital in Tucson said they do not know what caused the leaks.
``One main focus is looking for problems with the welding between different sections of tubing and other polymer components the tubing is attached to, with the goal of seeing whether there is some type of air leak,'' said Mark Bruley, vice president of accident and forensic investigation with ECRI, a medical research lab in Plymouth Meeting, Pa. ECRI was hired by St. Mary's.
``The testing is still ongoing and it's too early to release definitive results,'' Bruley said.
An FDA spokeswoman confirmed that problems also have surfaced at three other facilities — in Miami Lakes, Fla.; Johnstown, Pa.; and Bayonne, N.J. The FDA staffer, who asked not to be identified, said other facilities have reported problems in response to FDA safety alerts, but she declined to identify them.
The FDA said there also are reports of problems with equipment from other companies, but the spokeswoman declined to provide details. No other recalls have been made, and FDA is not urging other manufacturers to recall their products, the spokeswoman said.
``Some blood has gotten into the machine either through the tubing or filters,'' she said.
FDA has not received any reports of injury or illness from the leaks and said the risk is very low.
Sabrina Dorsey, a St. Mary's spokeswoman, said as many as 121 patients in the facility's acutecare inpatient center could have been exposed from Jan. 11-March 25. Some of the patients since have died from other problems and almost all have been tested, Dorsey said.
A Nissho Nipro statement said the company thinks the health risk is low because blood from one patient would have to get past the filter into the machine, and then make it back through the filter a second time when more disposable tubing is hooked up for another patient.
``Dialysis patients and their families should not be overly alarmed,'' the company said. ``Nissho Nipro does not believe our blood-tube products present an imminent hazard or serious health threat to patients.''
The company said it has received no reports of incidents outside the United States.
Nissho's U.S. subsidiary, Nipro Medical Corp., is in Miami. Both are owned by Nissho Corp. in Osaka, Japan. They distributed 2.1 million of the tubing sets in the United States in the past year.