Already squeezed financially because insurance companies and government agencies are paying less for health care services, doctors and hospitals say they increasingly face the added burden of having to wait months for their money.

The result, hospitals and doctors say, is that they spend more to collect insurance claims, and some say they are threatened with financial disaster because of too many long-overdue payments. Insurers respond that cost-control pressures force them to scrutinize bills more closely than before. They deny causing intentional delays.

But health care providers say they see many unnecessary roadblocks to timely bill collection. Not surprisingly, some doctors and hospitals who are most seriously affected serve a large percentage of Medicare and Medicaid patients. However, health care executives reserved their harshest criticism for private insurers, who the executives say do not have the excuse of lack of funds.

Some say it can be a struggle simply getting certain insurance companies to acknowledge receipt of a claim. "We're finding that we have to submit claims three or four times because they 'never received it,' " says Edward Prunchunas, chief financial officer for Northridge Hospital in Northridge, Calif.

The "lost" claim, hospitals and doctors say, is a delaying tactic employed by some insurers, including operators of health maintenance organizations and preferred provider organizations, who frequently pay claims well beyond the 30-day limit set by law. Some providers say that the law, which requires such third-party payers to pay interest if they delay beyond the limit, is unenforceable.

D. Mark Weinberg, executive vice president for consumer services at Blue Cross of California, denies that his firm uses that tactic and says he has never heard such a complaint from a health care provider. Even when insurers acknowledge a claim, providers say, they frequently impose endless reviews and nitpicking questions, such as a delay caused when an obstetrician neglected to state the sex of the patient on a claim for childbirth costs.

Prunchunas cited the case of a $150,000 trauma claim from an automobile accident. The claim was eventually denied by the insurer, who decided there was a "pre-existing condition" because the patient was drinking before the accident, he said. What bothered Prunchunas as much as the claim's rejection was the fact that it took the insurer 10 months to decide.

For consumers, the danger is being caught in the crossfire. When insurers and providers disagree over payments, the bill may very well end up in the mailbox of a patient.

Industry representatives maintain that there has been no increase in the turnaround time in the last three years.

Based on reports from its member companies, the Health Insurance Association of America -- the industry's main trade group -- said that most claims are processed within 14 days and only about 17 percent of claims are delayed. The data came from 74 of 240 companies that responded and represented about 50 percent of the nation's commercial health insurance business, HIAA says.

"The standard we set is that we try to process 85 percent of all claims within 14 days and 99 percent within 30 days," Blue Cross's Weinberg says. Regarding complaints about slow payments, he adds, "I think there are perception issues here." Health care providers think there are delays, he says, because in the new managed care environment they get fewer direct payments from patients and have to give far more details to insurers in order to get paid.

"Sometimes, we get an English language description of {services provided} but no codes . . . We can't . . . guess what was done," Weinberg says. Claims may be reviewed at several levels for different reasons, such as that the amount is very large or there are "illogical" descriptions.

But the problem is more than just a perception, says David Langness of the Hospital Council of Southern California. Contrary to insurance industry data, he says, "the turnaround time has elongated way past what it used to be. Sixty to 90 days was the norm . . . 100 days is more normal, and we hear about six- to 12-month delays."