Two patients at Fox Chase Cancer Center in Philadelphia required additional surgery last summer after objects were accidentally left inside their bodies, state health investigators found.

Three patients at Mercy Fitzgerald Hospital in Darby had to be sent back to the OR last year to stop excessive postoperative bleeding.

At Abington Memorial Hospital, an elderly woman recovering from surgery for a broken hip in 2005 was left on a bedpan for at least 41/2 hours. She developed two open bedsores as a result.

None of the hospitals reported the problems, a violation of state law, according to the Pennsylvania Department of Health.

For several years now, hospitals in Pennsylvania and New Jersey have been required to report medical mistakes and serious complications to state agencies charged with reducing medical errors. But some hospitals aren't fully complying, undermining efforts to improve patient safety, experts say.

In New Jersey, five of the state's 80 hospitals failed to report a single preventable mistake last year, officials said. In Pennsylvania, some facilities didn't report any serious events or even the near misses that might have harmed patients.

"I don't know how many is enough, but zero is a bad number," said James Bagian, head of the Department of Veterans Affairs' National Center for Patient Safety.

"Anybody that is supposed to report close calls and has zero reports is clueless," he said. "Management is asleep at the switch and just waiting until they kill someone."

There currently is no way for consumers to know how local hospitals are doing. Agencies in both states declined requests by The Inquirer to release the number of reports from individual hospitals. So the public can only learn that a hospital isn't reporting mistakes in those rare instances when the health department cites it for failing to comply with the law.

Twenty-six states require hospitals to report mistakes, and by next year Massachusetts, California and Minnesota will make the reports public.

Hospital associations in both Pennsylvania and New Jersey say members are training more staff and working to improve treatment in everything from medication safety to fall prevention.

"We are only a few years into this process," said Aline Holmes of the New Jersey Hospital Association, and "we have seen a steady increase in reporting."

Pennsylvania's mandatory-reporting law, passed in 2002, established the Patient Safety Authority and requires hospitals to report events that result in death or an "unanticipated" harm. Hospitals are also required to report near misses.

New Jersey's 2004 law makes hospitals report serious incidents, based on "never events," a list of 28 problems that should never happen. They include surgery on the wrong patient, an infant discharged to the incorrect person, serious injury from incompatible blood transfusions, and death or serious injury due to a medication error.

Since reporting began in February 2005, the health department has received 1,600 reports - about 20 per hospital for the 31/2-year period - and an analysis of each case.

"There is still some underreporting, and we are working directly with the hospitals to understand why," said Eliot Fishman, policy director of the New Jersey Department of Health and Senior Services.

Fishman said that the state had not cited any hospitals for failing to report but that it was helping them improve their internal safety systems.

Consumer advocates want more transparency so patients can make better health-care decisions.

"All the experts we have talked to have told us that there is not enough reporting going on to reflect the real number of major adverse events occurring in New Jersey hospitals," said Doug Johnston, chief lobbyist for AARP of New Jersey.

The senior citizens' group and Consumers Union are asking the agency to release hospitals' reports to the public, as it will do with hospital-acquired infection rates.