For the second time in a year, people who received tendons, cartilage and other parts from donated cadavers are being urged to get tested for hepatitis and the AIDS virus because of scandals involving tissue suppliers.

How much risk do they face?

Answering that is tough right now because federal officials will not say how many people around the country had received tissue by the time recalls were announced. Or which types of tissue were involved and how it was treated.

Patients may not even be aware they received cadaver tissue, which is used for everything from back surgery to dental implants.

Not all doctors even tell their patients they'll be getting donated human tissue. Doctors themselves often don't know where the tissue came from -- especially since it often is procured, tested and treated by different companies.

However, two steps can give patients a pretty good idea of their potential risks, experts say:

* Pressing your doctor for details on the companies that supplied your tissue and whether any are involved in the recalls.

* Getting the infectious disease tests that health officials recommend -- HIV, hepatitis B and C, and syphilis.

"If they're six months out [from the transplant] and they test negative, they don't have to worry," said Dr. L. Clifford McDonald, an infectious disease specialist at the federal Centers for Disease Control and Prevention. Chances are good that an infection would have taken hold by then, or at least shown up in blood tests, he said.

1.3 million possibilities

More than 1.3 million procedures each year -- ranging from knee repairs to cornea transplants to spine surgeries -- use tissue from donated cadavers. Most are supplied by reputable companies and do a lot of good, but the industry is little regulated, a three-month Associated Press investigation found earlier this year.

On Aug. 18, the U.S. Food and Drug Administration shut down Philip Guyett Jr. and Donor Referral Services of Raleigh, N.C., citing "serious deficiencies" in manufacturing practices. In some cases, records did not match what official death certificates showed, and left out details like a donor's history of cancer or drug use that may have made the donor's tissue ineligible for transplant, the FDA's order says.

On Wednesday, the FDA urged doctors to contact patients who received tissue from the firm, saying that additional information "has heightened our concern."

Companies voluntarily recalling tissue supplied by the Raleigh firm are Alamo Tissue Services of San Antonio; Lost Mountain Tissue Bank of Kennesaw, Ga.; TissueNet of Orlando, Fla.; and U.S. Tissue and Cell of Cincinnati. (AlloSource of Centennial, Colo., which acquired some of U.S. Tissue's assets in March, is handling U.S. Tissue's recall).

However, tissue typically is distributed nationwide, so patients anywhere could be affected.

A donor's reach

An industry group, the American Association of Tissue Banks, estimates that fewer than 100 donors are involved in the Raleigh company's case. But each donor can provide 100 or more tissue products, and the company also operated in Las Vegas from 2004 to 2005, the FDA notes.

Still, an association statement says this case appears much smaller in scope than one earlier this year involving Biomedical Tissue Services, a now-defunct New Jersey company that may have provided up to 20,000 potentially risky tissue products.

Good treatment and processing methods can make tissue safe "even if it was not screened properly or came from an infected donor," said Dr. Marion Kainer, a Tennessee Department of Health expert.